a barn has a gable roof whose rafters are 20 feet long. the width of the barn is 30 feet. find the angle that the rafters make with the horizontal. find the area of one of the gable ends.

1 answer

make a sketch by drawing in the height, calling it h
by Pythagoras:
h^2 + 15^2 = 20^2
h^2 = 175
h = √175

area = (1/2) base x height
= (1/2)(30)√175
=....

for angle:
tanØ = √175/15
I get Ø to be appr 41.4°