The area of the shaded region is 78 square inches. All angles are right angles and all measurements are given in inches. What is the perimeter of the non-shaded region?
The area of the small rectangle at the bottom right is 4 * 2 = 8 in^2
So....the rest of the shaded area must be 70 in ^2
But the dimensions the whole figure less the small rectangle at the bottom right are 10 * 8 = 80 in^2
So....the area of the non-shaded area in the middle must just be 80 - 70 = 10 in^2
So...since its height = 2 ..its width must be 5 in
And its perimeter must be 2 (2 + 5 ) = 14 in