Please help! :( i dont understand

So, you would dissect the shape by continuing to draw a line below the line with an eight to make a triangle and rectangle. we already know the perimeter of the sides we have (62) but we are missing the long side. so, you would have to find the pythagorean theorem of the right triangle using a^2 + b^2 equal c^2. we have a and b (20 and 10) so continue to solve the equation until you get about 22.3606 for the longest side. add that to 62 and get about 84.36 as the final answer. i hope this wasn’t confusing.

C