So, the cosineof is about. If you look in the table,you can see that an anglethat measures
has a cosineof. So, measuresabout. This is a right triangle.LessonSummary
In this lesson,we exploredhow to workwith differenttrigonometricratiosboth in theoryand in practicalsit-
uations.Specifically, we havelearned:
- The differentpartsof right triangles.
- How to identifyand use the sine ratio in a right triangle.
- How to identifyand use the cosineratio in a right triangle.
- How to applysine and cosineratiosin specialright triangles.
Theseskillswill help you solvemanydifferenttypesof problems.Alwaysbe on the lookoutfor new and in-
terestingwaysto find relationshipsbetweensidesand anglesin triangles.
Pointsto Consider
Beforeyou beginthe next lesson,thinkaboutstrategiesyou coulduse to simplifyan equationthat contains
a trigonometricfunction.
Note,you can only use the , , and ratioson the acuteanglesof a right triangle.For now it only
makessenseto talk aboutthe , , or ratio of an acuteangle.Laterin your mathematicsstudies
you will redefinetheseratiosin a way that you can talk about , , and of acute,obtuse,and
evennegativeangles.
LessonExercises
Use the followingdiagramfor exercises1-3.
- Whatis the sine of
- Whatis the cosineof
- Whatis the cosineof
Use the followingdiagramfor exercises4-6.