Answer:
a: 15 in
b:210 cm
c: 21 yds
Step-by-step explanation:
a: to find the area of a triangle multiply the base and the height, then divide the result by two.
b: to find the area of a trapezoid, multiply the median ( the point where the opposite corners cross) and the height.
c: to find the area of a parallelogram, multiply the lenght and the height.
Hope this helps!