Question

a trapezoid has an area of 20cm squared and a height of 5 cm. what is the sum of its top and bottom sides

Answer 1

$A=\frac{a+b}{2} h$
A - area
h - height
a+b - sum of its top and bottom sides

$20=\frac{a+b}{2} \cdot 5 \\ 4 = \frac{a+b}{2} \\ a+b=8$

The sum of its top and bottom sides is 8 cm.