# Activities

• ##### Download

• • ##### Subject Area

• Math: Precalculus: Trigonometric Laws and Identities

• ##### Author 9-12

45 Minutes

• ##### Device
• TI-Nspire™ CX/CX II
• TI-Nspire™ CX CAS/CX II CAS
• TI-Nspire™ Navigator™
• TI-Nspire™
• TI-Nspire™ CAS
• ##### Software

TI-Nspire™
TI-Nspire™ CAS

3.2

Law of Sines

#### Activity Overview

This lesson involves exploring the relationship known as the Law of Sines.

#### Objectives

• Students will understand how the Law of Sines is derived.
• Students will understand when the Law of Sines can be used to find missing sides and angles in a triangle.
• Students will be able to solve for missing sides and angles in a triangle using the Law of Sines, when appropriate.

#### Vocabulary

• sine of an angle
• obtuse angle
• acute angle
• right angle
• Ambiguous Case of the Law of Sines

#### About the Lesson

This lesson involves exploring the relationship known as the Law of Sines.
As a result, students will:

• Manipulate a triangle to observe the equality of ratios of side lengths and sines of opposite angles.
• Manipulate a triangle to decide when the Law of Sines gives an unambiguous result.
• Consider the Law of Sines in connection with previous knowledge about right triangle trigonometry.
• Determine when the Law of Sines can be used to solve for unknown side lengths and angle measures in a triangle, and apply it to solve when possible.