# A square plywood platform has a perimeter which is 7 times the length of a side, decreased by 12. How do you find the length of a side?

Jul 4, 2017

The length of a side is $28$ unit.

#### Explanation:

The perimeter of square platform with sides $a$ is $4 a$.

In given condition , $4 a = 7 \left(a - 12\right) \mathmr{and} 4 a = 7 a - 84 \mathmr{and} 7 a - 4 a = 84$ or

$3 a = 84 \mathmr{and} a = 28$ unit

The length of a side is $28$ unit [Ans]