http://www.ck12.org Chapter 8. Right Triangle Trigonometry
sin 30◦= 126 =^12 ,cos 30◦=^6
√
3
12 =
√
3
2 , and tan 30◦=^6
6√
3
= √^1
3
·
√
√^3
3
=
√
3
3.
Watch this video for help with the Examples above.
MEDIA
Click image to the left for more content.CK-12 Foundation: Chapter8SineCosineTangentB
Concept Problem Revisited
The trigonometric ratios for the non-right angles in the triangle above are:
sinA=^45 ,cosA=^35 ,tanA=^43 ,sinB=^35 ,cosB=^45 ,and tanB=^34.
Vocabulary
Trigonometryis the study of the relationships between the sides and angles of right triangles. The legs are called
adjacentoroppositedepending on whichacuteangle is being used. The three trigonometric (or trig) ratios are
sine,cosine, andtangent.
Guided Practice
Answer the questions about the following image. Reduce all fractions.
- What is sinA?
- What is cosA?
- What is tanA?
Answers:
- sinA=^1620 =^45
- cosA=^1220 =^35
- tanA=^1612 =^43
Practice
Use the diagram to fill in the blanks below.
- tanD=??
- sinF=??
- tanF=??
- cosF=??
- sinD=??
- cosD=??
From questions 1-6, we can conclude the following. Fill in the blanks.