u need to do the first one separately.
Length x width
10x20=200 cm^2 (area of rectangle)
base x height divided by 2
10x (10+10, the height of the triangle) divided by 2 = 100 divided by 2 = 50 cm ^2
now u need to add them together so u can find the area of the shape
50+200=250 cm^2
2nd question
length x width x height
10x 5x 2 = 100 cm^3