The area of a trapezoid = (1/2) * (altitude) * (sum of bases) = 69.6 in²
Altitude = 8.7 in
∴ (1/2) * 8.7 * (sum of bases) = 69.6
sum of bases = 2 * 69.6 / 8.7 = 16 in
And
sum of bases = sum of legs ⇒⇒⇒⇒⇒⇒ (Given)
∴ sum of legs =16 in
The perimeter of the trapezoid = sum of bases + sum of legs = 16 +16 = 32 in