CK-12-Pre-Calculus Concepts

http://www.ck12.org Chapter 4. Basic Triangle Trigonometry

tan 65◦= 10 x

x=10 tan 65◦≈ 30. 8 f t

Vocabulary

Thesix trigonometric ratiosare universal proportions that are always true of similar triangles (triangles with
congruent corresponding angles).
θ(theta)is a Greek letter and is just a letter used in math to stand for an unknown angle.

Guided Practice

1. Given 4 ABCwhereBis a right angle,m^6 C= 18 ◦, andc=12. What isa?


2. Given 4 XY ZwhereZis a right angle,m^6 X= 1 radian, andx=3. What isz?


3. Given 4 MNOwhereOis a right angle,m=12, andn=14. What is the measure of angleM?
   Answers:


4. Drawing out this triangle, it looks like:

tan 18◦=^12 a

a=tan 18^12 ◦≈ 36. 9