Find Rectangle Area by Tiling

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3rd Grade Math › Find Rectangle Area by Tiling

Questions 1 - 10
1

A tiled rectangle has $3$ rows of $5$ squares; what is the area?​

8 square units

12 square units

16 square units

15 square units

Explanation

This question tests 3rd grade area: finding the area of a rectangle by tiling it with unit squares, and showing that the area equals the product of the side lengths (CCSS.3.MD.7.a). When we tile a rectangle with unit squares, we create rows and columns. For example, a 3-by-5 rectangle has 3 rows with 5 squares in each row, giving 3×5=15 total squares. Multiplying the side lengths (length × width) gives the same answer as counting all the tiles because multiplication counts equal groups efficiently. The rectangle has dimensions 3 by 5. When tiled with unit squares, it has 3 rows of 5 squares each (or 5 columns of 3 squares each). Choice C is correct because 3 rows of 5 squares = 3×5 = 15 square units, which can be verified by counting all tiles OR multiplying length times width: 3×5=15. This shows understanding that tiling and multiplication give the same area. Choice B represents adding instead of multiplying, wrong calculation, perimeter confusion, missing units. This typically happens because students confuse addition with multiplication, miscalculate or miscount, confuse area (inside space) with perimeter (distance around), or forget area is measured in square units. To help students: Use physical tiles or graph paper to build rectangles, then count AND multiply to see they match. Show that '3 rows of 5' means 5+5+5 (repeated addition) which equals 3×5 (multiplication). Practice with various rectangle sizes: 2×4, 3×5, 4×6. Help students see the connection: rows × squares per row = total squares. Watch for: Students who add dimensions instead of multiply (3+5 instead of 3×5), students who confuse area with perimeter, students who multiply but forget to say 'square units,' and students who don't connect the visual tiling to the multiplication. Use the language 'rows of' to bridge to multiplication: 'I see 4 rows of 7 squares, so 4 times 7 equals 28.' This develops fluency with multiplication as counting equal groups while building area understanding.

2

A garden is $5$ meters by $4$ meters in $1$-meter squares; what area?

16 square meters

18 square meters

20 square meters

9 square meters

Explanation

This question tests 3rd grade area: finding the area of a rectangle by tiling it with unit squares, and showing that the area equals the product of the side lengths (CCSS.3.MD.7.a). When we tile a rectangle with unit squares, we create rows and columns. For example, a 3-by-5 rectangle has 3 rows with 5 squares in each row, giving 3×5=15 total squares. Multiplying the side lengths (length × width) gives the same answer as counting all the tiles because multiplication counts equal groups efficiently. The rectangle has dimensions 5 meters by 4 meters. When tiled with unit squares, it has 5 rows of 4 squares each (or 4 columns of 5 squares each). Choice C is correct because 5 rows of 4 squares = 5×4 = 20 square meters, which can be verified by counting all tiles OR multiplying length times width: 5×4=20. This shows understanding that tiling and multiplication give the same area. Choice B represents adding instead of multiplying, wrong calculation, perimeter confusion, missing units. This typically happens because students confuse addition with multiplication, miscalculate or miscount, confuse area (inside space) with perimeter (distance around), or forget area is measured in square units. To help students: Use physical tiles or graph paper to build rectangles, then count AND multiply to see they match. Show that '3 rows of 5' means 5+5+5 (repeated addition) which equals 3×5 (multiplication). Practice with various rectangle sizes: 2×4, 3×5, 4×6. Help students see the connection: rows × squares per row = total squares. Watch for: Students who add dimensions instead of multiply (3+5 instead of 3×5), students who confuse area with perimeter, students who multiply but forget to say 'square units,' and students who don't connect the visual tiling to the multiplication. Use the language 'rows of' to bridge to multiplication: 'I see 4 rows of 7 squares, so 4 times 7 equals 28.' This develops fluency with multiplication as counting equal groups while building area understanding.

3

This $5$ by $8$ rectangle is tiled; what is its area?​

18 square units

26 square units

40 square units

13 square units

Explanation

This question tests 3rd grade area: finding the area of a rectangle by tiling it with unit squares, and showing that the area equals the product of the side lengths (CCSS.3.MD.7.a). When we tile a rectangle with unit squares, we create rows and columns. For example, a 3-by-5 rectangle has 3 rows with 5 squares in each row, giving 3×5=15 total squares. Multiplying the side lengths (length × width) gives the same answer as counting all the tiles because multiplication counts equal groups efficiently. The rectangle has dimensions 5 by 8. When tiled with unit squares, it has 5 rows of 8 squares each (or 8 columns of 5 squares each). Choice C is correct because 5 rows of 8 squares = 5×8 = 40 square units, which can be verified by counting all tiles OR multiplying length times width: 5×8=40. This shows understanding that tiling and multiplication give the same area. Choice A represents adding instead of multiplying, wrong calculation, perimeter confusion, missing units. This typically happens because students confuse addition with multiplication, miscalculate or miscount, confuse area (inside space) with perimeter (distance around), or forget area is measured in square units. To help students: Use physical tiles or graph paper to build rectangles, then count AND multiply to see they match. Show that '3 rows of 5' means 5+5+5 (repeated addition) which equals 3×5 (multiplication). Practice with various rectangle sizes: 2×4, 3×5, 4×6. Help students see the connection: rows × squares per row = total squares. Watch for: Students who add dimensions instead of multiply (3+5 instead of 3×5), students who confuse area with perimeter, students who multiply but forget to say 'square units,' and students who don't connect the visual tiling to the multiplication. Use the language 'rows of' to bridge to multiplication: 'I see 4 rows of 7 squares, so 4 times 7 equals 28.' This develops fluency with multiplication as counting equal groups while building area understanding.

4

A rectangle is $4$ units by $7$ units; count or multiply for area.

18 square units

15 square units

22 square units

28 square units

Explanation

This question tests 3rd grade area: finding the area of a rectangle by tiling it with unit squares, and showing that the area equals the product of the side lengths (CCSS.3.MD.7.a). When we tile a rectangle with unit squares, we create rows and columns. For example, a 3-by-5 rectangle has 3 rows with 5 squares in each row, giving 3×5=15 total squares. Multiplying the side lengths (length × width) gives the same answer as counting all the tiles because multiplication counts equal groups efficiently. The rectangle has dimensions 4 by 7. When tiled with unit squares, it has 4 rows of 7 squares each (or 7 columns of 4 squares each). Choice B is correct because 4 rows of 7 squares = 4×7 = 28 square units, which can be verified by counting all tiles OR multiplying length times width: 4×7=28. This shows understanding that tiling and multiplication give the same area. Choice A represents adding instead of multiplying, wrong calculation, perimeter confusion, missing units. This typically happens because students confuse addition with multiplication, miscalculate or miscount, confuse area (inside space) with perimeter (distance around), or forget area is measured in square units. To help students: Use physical tiles or graph paper to build rectangles, then count AND multiply to see they match. Show that '3 rows of 5' means 5+5+5 (repeated addition) which equals 3×5 (multiplication). Practice with various rectangle sizes: 2×4, 3×5, 4×6. Help students see the connection: rows × squares per row = total squares. Watch for: Students who add dimensions instead of multiply (3+5 instead of 3×5), students who confuse area with perimeter, students who multiply but forget to say 'square units,' and students who don't connect the visual tiling to the multiplication. Use the language 'rows of' to bridge to multiplication: 'I see 4 rows of 7 squares, so 4 times 7 equals 28.' This develops fluency with multiplication as counting equal groups while building area understanding.

5

Jamal counted $12$ tiles and Sofia multiplied $3\times4$; what do you notice?​

Counting gives 10 and multiplying gives 12 square units

Counting gives 12 and multiplying gives 16 square units

Counting gives 12 and multiplying gives 12 square units

Counting gives 12 and multiplying gives 7 square units

Explanation

This question tests 3rd grade area: finding the area of a rectangle by tiling it with unit squares, and showing that the area equals the product of the side lengths (CCSS.3.MD.7.a). When we tile a rectangle with unit squares, we create rows and columns. For example, a 3-by-5 rectangle has 3 rows with 5 squares in each row, giving 3×5=15 total squares. Multiplying the side lengths (length × width) gives the same answer as counting all the tiles because multiplication counts equal groups efficiently. The rectangle has dimensions 3 by 4, with Jamal counting 12 tiles and Sofia multiplying 3×4=12. Choice A is correct because counting gives 12 and multiplying gives 12 square units, which can be verified by both methods matching for 3 rows of 4 squares = 3×4=12. This shows understanding that tiling and multiplication give the same area. Choice B represents adding instead of multiplying, wrong calculation, perimeter confusion, missing units. This typically happens because students confuse addition with multiplication, miscalculate or miscount, confuse area (inside space) with perimeter (distance around), or forget area is measured in square units. To help students: Use physical tiles or graph paper to build rectangles, then count AND multiply to see they match. Show that '3 rows of 5' means 5+5+5 (repeated addition) which equals 3×5 (multiplication). Practice with various rectangle sizes: 2×4, 3×5, 4×6. Help students see the connection: rows × squares per row = total squares. Watch for: Students who add dimensions instead of multiply (3+5 instead of 3×5), students who confuse area with perimeter, students who multiply but forget to say 'square units,' and students who don't connect the visual tiling to the multiplication. Use the language 'rows of' to bridge to multiplication: 'I see 4 rows of 7 squares, so 4 times 7 equals 28.' This develops fluency with multiplication as counting equal groups while building area understanding.

6

This $5$ by $8$ rectangle is tiled; what is its area?

18 square units

40 square units

13 square units

26 square units

Explanation

This question tests 3rd grade area: finding the area of a rectangle by tiling it with unit squares, and showing that the area equals the product of the side lengths (CCSS.3.MD.7.a). When we tile a rectangle with unit squares, we create rows and columns. For example, a 3-by-5 rectangle has 3 rows with 5 squares in each row, giving 3×5=15 total squares. Multiplying the side lengths (length × width) gives the same answer as counting all the tiles because multiplication counts equal groups efficiently. The rectangle has dimensions 5 by 8. When tiled with unit squares, it has 5 rows of 8 squares each (or 8 columns of 5 squares each). Choice C is correct because 5 rows of 8 squares = 5×8 = 40 square units, which can be verified by counting all tiles OR multiplying length times width: 5×8=40. This shows understanding that tiling and multiplication give the same area. Choice A represents adding instead of multiplying, wrong calculation, perimeter confusion, missing units. This typically happens because students confuse addition with multiplication, miscalculate or miscount, confuse area (inside space) with perimeter (distance around), or forget area is measured in square units. To help students: Use physical tiles or graph paper to build rectangles, then count AND multiply to see they match. Show that '3 rows of 5' means 5+5+5 (repeated addition) which equals 3×5 (multiplication). Practice with various rectangle sizes: 2×4, 3×5, 4×6. Help students see the connection: rows × squares per row = total squares. Watch for: Students who add dimensions instead of multiply (3+5 instead of 3×5), students who confuse area with perimeter, students who multiply but forget to say 'square units,' and students who don't connect the visual tiling to the multiplication. Use the language 'rows of' to bridge to multiplication: 'I see 4 rows of 7 squares, so 4 times 7 equals 28.' This develops fluency with multiplication as counting equal groups while building area understanding.

7

Emma arranges square tiles to make a rectangle. She makes $$4$$ rows, and each row has $$7$$ tiles. Then she rearranges the same tiles to make a different rectangle with $$2$$ rows. How many tiles are in each row of the new rectangle?

$$12$$ tiles per row, and the area stays $$24$$ square units

$$9$$ tiles per row, and the area stays $$28$$ square units

$$14$$ tiles per row, and the area stays $$28$$ square units

$$16$$ tiles per row, and the area stays $$32$$ square units

Explanation

The original rectangle has 4 × 7 = 28 tiles total. When rearranged into 2 rows, each row must have 28 ÷ 2 = 14 tiles. The area remains 28 square units because the same tiles are used.

8

Mrs. Chen's class tiles a rectangular bulletin board. They use $$42$$ square tiles total. The rectangle is $$6$$ tiles wide. After tiling, they realize they could make the same area using a rectangle that is $$7$$ tiles wide instead. How many rows would the new rectangle have?

$$5$$ rows because $$7 \times 5 = 35$$ which is close to $$42$$

$$7$$ rows because $$7 \times 7 = 49$$ which is close to $$42$$

$$8$$ rows because $$7 \times 8 = 56$$ which is close to $$42$$

$$6$$ rows because $$7 \times 6 = 42$$ matches the original area

Explanation

When you see a problem about rearranging rectangular areas, remember that the total area must stay the same no matter how you change the dimensions. This is a key principle in geometry problems.

Let's work through this step by step. First, we need to find the total area of the original bulletin board. We know they used 42 square tiles total, so the area is 42 square tiles. We can verify this makes sense: if the rectangle is 6 tiles wide, then $$42 \div 6 = 7$$ rows, giving us $$6 \times 7 = 42$$ tiles.

Now, for the new rectangle that's 7 tiles wide, we need to find how many rows will give us the same area of 42 square tiles. We divide: $$42 \div 7 = 6$$ rows. Let's check: $$7 \times 6 = 42$$. Perfect! This matches our original area exactly.

Looking at the wrong answers: Choice A gives us $$7 \times 5 = 35$$ tiles, which is 7 tiles short of our needed 42. Choice B gives us $$7 \times 8 = 56$$ tiles, which is 14 tiles too many. Choice D gives us $$7 \times 7 = 49$$ tiles, which is 7 tiles too many. These answers all use the phrase "close to 42," but in mathematics, we need exact answers, not approximations.

The correct answer is C because $$7 \times 6 = 42$$ matches the original area exactly.

Strategy tip: In area problems, always check that your new dimensions give you exactly the same total area as the original—close isn't good enough!

9

Jake tiles two rectangles. Rectangle A has $$3$$ rows of $$6$$ tiles each. Rectangle B has $$2$$ rows of $$9$$ tiles each. Jake says Rectangle B has a larger area because $$9 > 6$$. Is Jake correct?

Yes, because Rectangle B has area $$19$$ and Rectangle A has area $$17$$, so B is larger

No, because Rectangle A has area $$21$$ and Rectangle B has area $$18$$, so A is larger

No, because Rectangle A has area $$18$$ and Rectangle B has area $$18$$, so they're equal

Yes, because Rectangle B has area $$20$$ and Rectangle A has area $$18$$, so B is larger

Explanation

When you see a problem about finding the area of rectangles made from tiles, you need to count all the tiles, not just focus on one dimension. Area means the total space inside a shape, which equals the number of rows times the number of tiles in each row.

Let's calculate each rectangle's area correctly. Rectangle A has 3 rows with 6 tiles each, so its area is $$3 \times 6 = 18$$ tiles. Rectangle B has 2 rows with 9 tiles each, so its area is $$2 \times 9 = 18$$ tiles. Both rectangles have exactly the same area of 18 tiles, so Jake is wrong. The fact that 9 is greater than 6 doesn't matter because Rectangle B has fewer rows.

Looking at the wrong answers: Choice A incorrectly calculates both areas (17 and 19 don't match our multiplication), but concludes Jake is right. Choice B also gets wrong areas (18 and 20) and agrees with Jake. Choice C gets Rectangle A's area wrong as 21, though it correctly identifies that Rectangle A would be larger if that were true. Only choice D correctly calculates both areas as 18 and recognizes they're equal.

Remember this key strategy: when comparing areas of tiled rectangles, always multiply rows times tiles per row for each rectangle. Don't just compare the bigger numbers you see - a rectangle with more tiles per row but fewer rows might actually have the same or smaller total area.

10

Maya tiles a rectangle using $$1$$-inch square tiles. She uses $$6$$ rows with $$4$$ tiles in each row. Then she removes one corner tile and adds $$3$$ more tiles to make a different shape. What was the area of the original rectangle?

$$25$$ square inches

$$24$$ square inches

$$23$$ square inches

$$26$$ square inches

Explanation

The original rectangle had 6 rows with 4 tiles each, so the area was 6 × 4 = 24 square inches. The changes Maya made afterward (removing and adding tiles) don't affect the area of the original rectangle.

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