# Trigonometry: using cosine

Learning Material, Learning Guide, Learning Module  |  Interactive Lesson  |  RAR

Published on 2018 August 1st

Description
Solve measurement problems involving right-angled triangles by using similar triangles and trigonometric methods, including cosine values. Identify corresponding sides and ratio relationships in similar triangles. Solve measurement problems by using cosine values to calculate side lengths in triangles. For example, find the width of a moat, given one angle and distance to the top of a castle. This learning object is one in a series of ten objects.
Objective
1. Students apply knowledge of relationships between sides of similar triangles to calculate side lengths in right-angled triangles.
2. Students use multiplicative and ratio strategies to solve measurement problems.

#### Curriculum Information

 Education Type K to 12 Grade Level Grade 9 Learning Area Mathematics Content/Topic Geometry Intended Users Learners, Students Competencies