Lesson 4

1. Lesson 4

1.7. Connect

Mathematics 20-1 Module 2

Module 2: Trigonometry

Connect

Lesson 4 Assignment

Open the Lesson 4 Assignment you saved in your course folder at the start of this lesson. Complete the assignment.

Save all your work in your course folder.

Going Beyond

Read “Proof” on page 102 of your textbook. This is only valid for acute triangles. Write a proof of the sine law for an obtuse triangle, such as the one shown.

This is a sketch of an obtuse triangle with vertices A, B, C, and corresponding sides a, b, c. Angle A is obtuse.

Start by extending segment and drawing a perpendicular segment to vertex C.

This is a sketch of an obtuse triangle with vertices A, B, C, and corresponding sides a, b, c. Angle A is obtuse. A right triangle has been created by extending segment AB past vertex A until it meets a perpendicular segment from vertex C. This perpendicular segment is labelled y.

Write the sine ratio for ∠B using and also for ∠DAC using