Question

What is the perimeter of the trapezoid above?

• A. $72$
• B. $80$
• C. $87$
• D. $75$
• E. $52$

Answer 1

Answer: (B)

In given figure, $AB=20,BC=15$ and $AD=17$

Draw perpendicular from point $A$ to line $CD$ meet at point $E$

Then $BC=AE=15$

So in $△AED$,

$DE=$ $\sqrt{(17{)}^2-(15{)}^2}=\sqrt{289-225}=\sqrt{64}=8$

Then $DC=DE+CE=8+20=28$ .......( $AB=CE=20$)

Then perimeter of trapezoid $=20+17+15+28=80$