The perimeter of any figure is the sum of the lengths of the sides: \(\displaystyle 12 + 18 + 20 = 50 \;ft\).

By the Pythagorean Theorem, if \(\displaystyle a\) and \(\displaystyle b\) are the legs of a right triangle and \(\displaystyle c\) is its hypotenuse, then 

\(\displaystyle a^{2} + b^{2} = c^{2}\).

Set \(\displaystyle b = 60, c= 65\) and solve for \(\displaystyle a\):

\(\displaystyle a^{2} + 60^{2} = 65^{2}\)

\(\displaystyle a^{2} + 3,600 = 4,225\)

\(\displaystyle a^{2} + 3,600 -3,600 = 4,225 -3,600\)

\(\displaystyle a^{2} = 625\)

\(\displaystyle \sqrt{a^{2}} =\sqrt{ 625}\)

\(\displaystyle a = 25\)

The perimeter of the triangle - the sum of the sidelengths - is 

\(\displaystyle P = 25 + 60 + 65 = 150\).

The perimeter is equal to the sum of the length of the sides. An equilateral triangle has three sides with equal lengths.

\(\displaystyle P=4+4+4=12\)

Perimeter involves adding up all of the sides of the shapes; in this case, it's a triangle. Perimeter equals \(\displaystyle 9+8+11\). Therefore, the answer is \(\displaystyle 28cm\).

The length of the hypotenuse of the triangle can be found using the Pythagorean Theorem. Substitute \(\displaystyle a = 9,b= 12\):

\(\displaystyle c = \sqrt{a ^{2} + b^{2} } =\sqrt{9 ^{2} +12^{2} } = \sqrt{81+144} = \sqrt{225} = 15\) feet

Its perimeter is \(\displaystyle P = 9 + 12 + 15 = 36\) feet. Multiply by 12 to get the perimeter in inches:

\(\displaystyle 36 \times 12 = 432\) inches

An equilateral triangle has three sides of equal measure, so divide its perimeter by \(\displaystyle 3\):

\(\displaystyle 73.5 \div 3 =24.5 \textrm{ cm}\)

To solve, you must first use the Pythagorean Theorem to solve for the hypotenuse and then add that value to the two perimeter values given.

Thus,

\(\displaystyle c^2=a^2+b^2\Rightarrow c=\sqrt{a^2+b^2}\)

\(\displaystyle c=\sqrt{5^2+12^2}=\sqrt{25+144}=\sqrt{169}=13\)

\(\displaystyle P=5+12+13=30\)

An equilateral triangle has three equal length sides.  

The perimeter of a triangle is all the sides added together.  

Since all the sides are the same length the equation 

\(\displaystyle s+s+s=18\) 

is equal to 

\(\displaystyle 3s=18\).  

To find the side length, you just need to divide the perimeter by \(\displaystyle 3\) which is 

\(\displaystyle 18/3=6\).

To find the perimeter of a triangle, we use the following formula:

\(\displaystyle \text{perimeter of triangle} = a+b+c\)

where a, b, and c are the sides of the triangle.  

Now, we know the triangle is equilateral.  This means that each side of the triangle is the same length.  We know one side is 11 inches.  Therefore, all sides are 11 inches.  Knowing this, we can substitute.  We get

\(\displaystyle \text{perimeter of triangle} = 11\text{ inches} + 11\text{ inches} + 11\text{ inches}\)

\(\displaystyle \text{perimeter of triangle} = 33 \text{ inches}\)

Find the perimeter of an equilateral triangle whose side measures 14 meters.

The perimeter of a shape is simply the distance around it. 

An equilateral triangle has three equal sides.

To find the perimeter in this case, simply multiply one side by 3.

\(\displaystyle P=3*14m=42m\)

So our answer is 42 meters.