No, this is because right angles can also be formed
31 students do their homework every night
The answer is 290. First calculate the area of the rectangle part on the bottom. area=20*9=180 square yards. Then calculate the area of the triangle on the top. Base length is 20, while the height is 20-9=11, so the area is 20*11/2=110. 180+110=290 square yards in total.
