Question

Alex is creating an outdoor structure out of two 12 foot boards. The boards must have an angle of elevation

of at least 40! in order for snow to slide off and must have a width of at least 8 feet (from point A to B) in
order to fit his snow blower.
What is the range of heights, h, that Alex's structure can have? Round to the nearest tenth of a foot and show
how you arrived at your range.

Answer 1

5.0 ft - 5.6 ft

Explanation:

Given that the structure is to be made using two 12 foot boards, then we expect the total perimeter to be equal to (2*12)= 24 ft.

Using the angle of elevation, 40° and the width of 8 ft then you can apply the formula for tangent of a triangle where ;

Tan α = opposite side length/adjacent length

Tan 40°= h/8

h= 8 tan 40° = 6.71 ft

Applying the cosine of an angle formula to find the length of the sliding side

Cosine β = adjacent length /hypotenuse

Cosine 40°= 8/ sliding side length

sliding side length = 8/cosine 40° =10.44 ft

Checking the perimeter = 10.44 +8+6.71= 25.15 ft

This is more than the total lengths of the boards, so you need to adjust the height as;

24 - 18.44 = 5.56 ft ,thus the height should be less or equal to 5.56 ft

h≤ 5.6 ft