Answer:
20.3
Step-by-step explanation:
From the image, we can clearly see that the two triangles are actually right triangles. They have a hypotenuse l of 21 ft. and a base b of 5.5 ft. So by applying the Pythagoreans formula we get height h,
[tex]l^2 = b^2 + h^2\\\implies h = \sqrt{l^2 - b^2}\\= \sqrt{21^2 - 5.5^2}\\= 20.3\\[/tex]
So the height is 20.3 ft.
