# Second Semester Geometry

## Chapter 8: Trigonometry

Key Ideas

• Pythagorean Theorum
• SOH-CAH-TOA Trigonomic Device
• Inverse ""
• Degree and Radian Measures
• Special Right Triangles
• Unit Circle

## Pythagorean Theorum

A squared + B squared = C squared (base squared + height squared = hypothenuse [longest side])

• Only works on right triangles ## Trigonometric Ratios

• The sides and the angles of triangles and the trigonometric functions are related.
• SOH CAH TOA
• Shows what the missing side measure is

## Inverse Trigonometric Functions

• Shows what the missing side measure is
• Sets it up like the picture shown ## Angle of Elevation/Depression

• Deals with viewpoint of people/things
• Used to find out how high or at what angle things are at

## 6 Trig Functions

Pretty straight forward. The formulas are in the picture. They are sine, cosine, tangent, cosecant, secant, and cotangent. ## Degree and Radian Measures

You can measure with both degrees and radians. In a unit circle, there are degrees and radians. The degree is obviously the angle measure of each angle, and the radian measure is what it is in terms of Pi.

• To rewrite a degree measure in radians, multiply be Pi radians over 180 degrees, and the reciprocal of that for radians to degree measure.
• You use the unit circle in these problems. ## Special Right Triangles

Theorem: In a 30-60-90 triangle the sides are in the ratio 1:2:the square root of 3

## Tips!

• Use a calculator it makes your life much easier
• Don't overthink the problem
• Write out ALL your work

## Things We Struggled With

• The Unit Circle and Radians. That was just hard to understand.
• Angle of Depression was hard at first, but with practice it got easier.