Answer:
20 units
Explanation:
1) find the side of the first square
side = P / 4 = 12:4 = 3 units
2) find the side of the second square
side = P / 4 = 16 : 4 = 4 units
3) use the Pythagorean theorem to find the hypotenuse of the right triangle
units
4) find the perimeter of the third square
P = side x 4 = 5 x 4 = 20 units