The area of any trapezoid is
Area = (1/2) x (height) x (one base + the other base) .
Take that formula and write in the numbers you know:
(24 m²) = (1/2) x (height) x (5m + 7m)
(24 m²) = (6m) x (height)
Divide each side by 6m :
Height = (24 m² / 6m)
= 4 m .
