Define trigonometric ratio
a ratio of the length of three sides of a right triangle
what are the three basic trigonometric ratios
sine: side opposite/hypotenuse
cosine: side adjacent/hypotenuse
tangent: side opposite/side adjacent
acronym to remember the three trigometric ratios
SOH - CAH - TOA
How to determine the trig ratio between two side lengths
1.) Pick a perspective
2.) Using that perspective, locate the side opposite, side adjacent, and the hypotenuse
3.) Plug those side lengths into the sin, cos, tan ratios and divide
How to find the sin/cos/tan for a single side length using a calculator
1.) Press DRG
2.) Press sin/cos/tan
3.) Type in the argument
4.) Press equals
How to find the sin/cos/tan for a side length in a proportion using a calculator
1.) Isolate the variable
2.) type in the side without the variable into your calculator exactly as it is
When to use trig ratios to find angles and side lengths
Side lengths:
When your given one side and an acute angle
Angles:
When your given no acute angles
How to find the measure of an angle given the sin/cos/tan using a calculator
1.) press 2nd
2.) press sin
3.) type in the trig ratio
4.) press equals
How to find a side length from a triangle using SOH-CAH-TOA
1.) Pick a perspective
2.) Determine which trig ratio relates a known side length to the missing side length
3.) Set that ratio equal to sin/cos/tan of the angle measure
4.) isolate the variable
5.) Type the side without the variable into the calculator
How to find a missing angle measure in a triangle
1.) Pick a perspective
2.) Determine which trig ratio relates a known side length to another known side length
3.) Set that ratio equal to the sin/cos/tan of the angle
4.) type into your calculator 2nd, sin/cos/tan, ratio
Trigonometry know how tos
Determine the trig ration between two side lengths
Determine the trig ration of a single side length by itself or in a proportion
Determine the trig ratio of a single angle measure
Find missing side lengths or angle measures using trig ratios
