The area of a trapdoor is 198 cm. The height is 18 cm and the length of one of the parallel sides is 7 cm. What is the length of the second parallel side.

Question

Answer as simplified fraction or a decimal rounded to two places.

Answer 1

If the opposite side was 7 cm, the total area is calculated as

18cm * 7cm = 126cm²

 

So we know the parallel side opposite to the 7cm side is longer than 7cm since the total  area is 198cm²

 

The length greater than 7cm and the side of 18cm form a right triangle.

 

The equation to find that area ( remaining area) of the triangle is

 

(1/2) * 18cm * X = 72  

 

Can you solve for X?

 

X will be the amount length of the opposite side in addition to the 7cm.  So you have to add 7 cm to X to get the length of the opposite side.