Answer:
12 ft
Step-by-step explanation:
we know the areas of the 2 top squares.
the area of a square is simply the square of its side length.
=>
81 ft² means side length is 9 ft.
225 ft² means side length is 15 ft.
these are also 2 of the sides of the right triangle.
the third side we get by using Pythagoras :
c² = a² + b²
with c being the side opposite of the 90 degree angle.
so,
225 = 81 + x²
as x is also the third side of the triangle.
=> 144 = x²
x = 12 ft
