Answer:
x = sqrt(5)
Step-by-step explanation:
The ratio of the areas is equal to the ratio of the side lengths squared
20 5^2
----- = -----
4 x^2
Using cross products
20 x^2 = 4 * 5^2
20x^2 = 4*25
20x^2 = 100
Divide by 20
20x^2 = 100/20
x^2 = 5
Take the square root of each side
sqrt(x^2) = sqrt(5)
x = sqrt(5)
