Answer:
24 feets
Explanation:
Area of a trapezium :
A=1/2(b1+b2)h
b1 = 30 ; b2 = 50 ; Area, A = 960ft²
Inputting values into the formula :
960 = 1/2(30 + 50) * h
960 = 1/2(80)h
960 * 2 = 80h
1920 = 80h
Divide both sides by 80
1920 / 80 = 80h / 80
24 = h
Height of backyard = 24 feets