Question

Arielle is building the wooden framework for the roof of a house. She needs the angle created by the vertical and horizontal boards of the frame to be a right angle. The height of the vertical board is 12 feet. The length of the horizontal board is 15 feet. The support beam that will connect the ends of the two boards measures 20 feet.

Answer 1

A² + b² = c²  ⇒ right triangle
a² + b² < c² ⇒ obtuse triangle
a² + b² > c² ⇒ acute triangle

a = 12 ft ; b = 15 ft ; c = 20 ft

12² + 15² = < > 20²
144 + 225 = < > 400
369 < 400 OBTUSE TRIANGLE

√369 = 19.21

20 - 19.21 = 0.79 

It is an obtuse triangle. About 0.8 foot needs to be removed from the 20-foot board to create a right triangle.