For the algebraic expression (m+3)(m+7) how would you solve this? write it out on steps so i can write it in my notebook

Part A: You use Pythagorean Theorem and get 289-64=225 square root which is 15. That is the height.

Part B: The triangles are 8*15 which is 120*2 because there are 2. The rectangles are 20*17 which is 340*3 because there are 3. This makes 240+1020=1260