Lesson 4

1. Lesson 4

1.6. Explore 2

Mathematics 20-3 Module 4

Module 4: The Right Kind Of Triangles

Example

A dual pitch truss is used in the construction of a large shed. The shallow pitch is 26.57° (or 6:12). The steep pitch is 36.87° (or 9:12) and has a side length of 10 ft. The truss shown in the diagram is positioned at one end of the shed, called the gable end. The gable end will be covered by plywood after framing the shed. On the diagram, the perimeter of the gable end is outlined in red. How much plywood is needed to cover this triangular area? Round your answer to the nearest tenth of a square foot.

This is an illustration of a dual pitch truss.

Solution

Watch Roof Truss to see how the problem can be solved. The Adjacent Right-Triangle Problem demonstration is another example of how a problem involving two triangles can be solved using trigonometry.

This is a play button that opens Roof Truss.

This is a play button that opens the Adjacent Right-Triangle Problem demonstration.

Self-Check 1

Solve for the unknown in the following adjacent right-triangle problem. You may choose to revisit the Adjacent Right-Triangle Problem demonstration for help.

This is an illustration of an adjacent right triangle.
Answer