SSAT Middle Level Math : Rectangles

Study concepts, example questions & explanations for SSAT Middle Level Math

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Example Questions

Example Question #31 : Quadrilaterals

The perimeter of a rectangle with a length of \(\displaystyle 10x\) and a width of \(\displaystyle 6x\) is \(\displaystyle 64\ in\). Find \(\displaystyle x\).

 

Possible Answers:

\(\displaystyle 1\)

\(\displaystyle 3\)

\(\displaystyle 2\)

\(\displaystyle 5\)

\(\displaystyle 4\)

Correct answer:

\(\displaystyle 2\)

Explanation:

We know that:

 

\(\displaystyle Perimeter=2(a+b)\)

 

where:

 

\(\displaystyle a=Length \ of\ the\ rectangle\)

\(\displaystyle b= Width\ of\ the\ rectangle\)

 

So we can write:

 

\(\displaystyle 64=2(10x+6x)\Rightarrow 10x+6x=32\Rightarrow 16x=32\Rightarrow x=2\)

Example Question #3 : How To Find The Perimeter Of The Rectangle

Rectangles

Note: Figure NOT drawn to scale.

Refer to the above diagram. Give the perimeter of the red polygon.

Possible Answers:

\(\displaystyle 240\)

\(\displaystyle 120\)

The perimeter cannot be determined from the information given.

\(\displaystyle 140\)

\(\displaystyle 340\)

Correct answer:

\(\displaystyle 240\)

Explanation:

Since opposite sides of a rectangle have the same measure, the missing sidelengths can be calculated as in the diagram below:

Rectangles

The sidelengths of the red polygon can now be added to find the perimeter:

\(\displaystyle 40 + 80 + 20 + 30 + 20 + 50 = 240\)

Example Question #4 : How To Find The Perimeter Of The Rectangle

The width of a rectangle is \(\displaystyle 3x\), the length is \(\displaystyle 6x\), and the perimeter is 72. What is the value of \(\displaystyle x\)?

Possible Answers:

\(\displaystyle 16\)

\(\displaystyle 36\)

\(\displaystyle 5\)

\(\displaystyle 4\)

\(\displaystyle 18\)

Correct answer:

\(\displaystyle 4\)

Explanation:

Start with the equation for the perimeter of a rectangle:

\(\displaystyle P=l+l+w+w=2l+2w\)

We know the perimeter is 72, the length is \(\displaystyle 6x\), and the width is \(\displaystyle 3x\). Plug these values into our equation.

\(\displaystyle 72=2(6x)+2(3x)\)

Multiply and combine like terms.

\(\displaystyle 72=12x+6x\)

\(\displaystyle 72=18x\)

Divide by 18 to isolate the variable.

\(\displaystyle \frac{72}{18}=x\)

Simplify the fraction by removing the common factor.

\(\displaystyle \frac{72}{18}=\frac{72\div18}{18\div18}=\frac{4}{1}=4\)

Example Question #5 : How To Find The Perimeter Of The Rectangle

Rectangles

Note: Figure NOT drawn to scale.

Refer to the above diagram. Give the ratio of the perimeter of the large rectangle to that of the smaller rectangle.

Possible Answers:

\(\displaystyle 12:5\)

The correct answer is not given among the other choices.

\(\displaystyle 8:3\)

\(\displaystyle 16:7\)

\(\displaystyle 2:1\)

Correct answer:

\(\displaystyle 12:5\)

Explanation:

Opposite sides of a rectangle are congruent.

The large rectangle has perimeter

\(\displaystyle 40 + 80 + 40 + 80 = 240\).

The smaller rectangle has perimeter

\(\displaystyle 20 + 30 + 20 + 30 = 100\).

The ratio is

\(\displaystyle \frac{240}{100} = \frac{240 \div 20 }{100\div 20 } = \frac{12}{5}\); that is, 12 to 5.

Example Question #3 : How To Find The Perimeter Of The Rectangle

What is the perimeter of a rectangle with a width of 3 and a length of 10?

Possible Answers:

12

30

13

60

26

Correct answer:

26

Explanation:

The formula for the perimeter of a rectangle is \dpi{100} Perimeter=2l+2w\(\displaystyle \dpi{100} Perimeter=2l+2w\).

Plug in our given values to solve:

\dpi{100} Perimeter = 2(20)+2(3)\(\displaystyle \dpi{100} Perimeter = 2(20)+2(3)\)

\dpi{100} Perimeter = 20+6\(\displaystyle \dpi{100} Perimeter = 20+6\)

\dpi{100} Perimeter = 26\(\displaystyle \dpi{100} Perimeter = 26\)

Example Question #121 : Geometry

Rectangle ABCD has an area of \(\displaystyle 40\).  If the width of the rectangle is \(\displaystyle 5\), what is the perimeter?

Possible Answers:

\(\displaystyle 13\)

\(\displaystyle 26\)

\(\displaystyle 40\)

\(\displaystyle 8\)

\(\displaystyle 16\)

Correct answer:

\(\displaystyle 26\)

Explanation:

The area of a rectangle is found by multiplying the length times the width.  The question tells you the width is \(\displaystyle 5\) and the area is \(\displaystyle 40\).  

Thus the length is 8. \(\displaystyle \left ( 40 \div5\right)\).

To find the perimeter you add up all of the sides.  

\(\displaystyle length+length+width+width=perimeter\)

 \(\displaystyle 8 + 8 + 5 + 5 = 26\)

Example Question #62 : Rectangles

If the perimeter of a rectangle is \(\displaystyle 14\) inches and the width is \(\displaystyle 2\) inches, what is the length?

Possible Answers:

\(\displaystyle 7\)

\(\displaystyle 5\)

\(\displaystyle 4\)

\(\displaystyle 6\)

\(\displaystyle 8\)

Correct answer:

\(\displaystyle 5\)

Explanation:

The perimeter of a rectangle is represented by the following formula, in which W represents width and L represents length:

\(\displaystyle 2W+2L= Perimeter\)

Given that the width is \(\displaystyle 2\) inches and that the perimeter is \(\displaystyle 14\) inches, the following applies:

\(\displaystyle 2\cdot 2+2L=14\)

\(\displaystyle 4+2L=14\)

Next, subtract \(\displaystyle 4\) from each side.

\(\displaystyle 2L=10\)

Now, divide each side by \(\displaystyle 2\).

This gives us

\(\displaystyle L=5\)

Example Question #11 : Rectangles

A rectangle has an area of \(\displaystyle 24\). The length of each side is a whole number. What is NOT a possible value for the rectangle's perimeter? 

Possible Answers:

\(\displaystyle 22\)

\(\displaystyle 20\)

\(\displaystyle 23\)

\(\displaystyle 50\)

\(\displaystyle 28\)

Correct answer:

\(\displaystyle 23\)

Explanation:

Since each side is a whole number, first find the whole number factors of \(\displaystyle 24\). They are \(\displaystyle 3\) and \(\displaystyle 8\), \(\displaystyle 12\) and \(\displaystyle 2\), \(\displaystyle 24\) and \(\displaystyle 1\), and \(\displaystyle 6\) and \(\displaystyle 4\). These sidelengths correspond to perimeters of \(\displaystyle 22\), \(\displaystyle 28\), \(\displaystyle 50\), and \(\displaystyle 20\), respectively. Thus, \(\displaystyle 23\) is answer. 

Example Question #2051 : Isee Middle Level (Grades 7 8) Mathematics Achievement

Rectangle

Give the perimeter of the above rectangle in centimeters, using the conversion factor \(\displaystyle 91.44\) centimeters per yard.

Possible Answers:

\(\displaystyle 1,097.28 \textrm{ cm}\)

\(\displaystyle 4,389.12 \textrm{ cm}\)

\(\displaystyle 1,005.84 \textrm{ cm}\)

\(\displaystyle 2,194.56 \textrm{ cm}\)

\(\displaystyle 2,011.68 \textrm{ cm}\)

Correct answer:

\(\displaystyle 2,011.68 \textrm{ cm}\)

Explanation:

The perimeter of the rectangle is \(\displaystyle 8 + 3 + 8 + 3 = 22\) yards. To convert this to centimeters, multiply by the given conversion factor:

\(\displaystyle 91.44 \times 22 = 2,011.68\) centimeters.

Example Question #11 : Rectangles

Find the perimeter of the rectangle shown below

Screen shot 2015 11 10 at 9.55.29 pm

Possible Answers:

\(\displaystyle 64\)

\(\displaystyle 30\)

\(\displaystyle 28\)

\(\displaystyle 36\)

\(\displaystyle 80\)

Correct answer:

\(\displaystyle 36\)

Explanation:

The perimeter of a rectangle, or any shape, is the distance around the outside. You add up the length of each side to find this number. The coordinates of the points are \(\displaystyle (-3,8)(5,8)(5,-2)(-3,-2)\). You need to find the distance between each point. The short side is \(\displaystyle 8\) units, and the longer side is \(\displaystyle 10\) units. 

\(\displaystyle (8\times2)+(10\times2)=16+20=36\)

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