So to find the perimeter you have to find the length of the diagonal lines. The definition of isosceles means that the shape has two sides of equal length. So you’d solve for te missing length using the Pythagorean theorem. The difference between the top side and the bottom is 10, which means that each side of the 90 degree is 5. So on the bottom it is 5,12,5 for measurements, meaning that the middle is a square with two right triangles.
Solve using the Pythagorean theorem
a^2+b^2=c^2 with This you should get 9.43 (rounded) as your values.
Then just add up the side lengths.
2(9.43)+22+12, which gives a perimeter of 52.87 (rounded)
