Answer:
640 cm²
Explanation:
The ratio of the area of 2 similar polygons = the ratio of the square of their corresponding lengths
Thus:
Area of Trapezoid ABCD to Area of Trapezoid EFGH = AB² to EF²
Area of Trapezoid ABCD = ? = x
Area of Trapezoid EFGH = 40 cm²
AB = 20 cm
EF = 5 cm
Substitute
x:40 = 20²:5²
x/40 = 400/25
x/40 = 16
Cross multiply
x = 16*40
x = 640
Area of trapezoid ABCD = 640 cm²