Answer:
6
Explanation:
Since the garden bed looks like the shape of a trapezoid the equation to find the area of a trapezoid is A = 1/2h (base 1 + base 2)
The area is already given so you can just plug it in. Also you can plug in the bases.
21 = 1/2h (3 + 4)
21 = 1/2h (7) rewrite
21 = 1/2(7)h
21 = 3.5h Divide both sides by 3.5
6 = h