# Lesson overview:Surds and triangles

- In this lesson, we will recap how to use Pythagorean theorem to find the length of missing sides in triangles leaving the answers is surd form.

## Core Content

- In this lesson, we will recap how to use Pythagorean theorem to find the length of missing sides in triangles leaving the answers is surd form.

## Surds and trigonometry:

- Rational and irrational numbers
- Introduction to Surds
- Surds and triangles
- Manipulating surds
- Varying the ratio of side lengths in right angle triangles
- The case of 30 and 60 degrees
- The sine ratio
- The sine and cosine ratios
- The sine and cosine ratios for 30 and 60 degrees
- Finding missing sides using sine and cosine for any angle
- Using inverse sine and cosine to find missing angles
- Sine and cosine graphs