8-3 TRIGONOMETRY
DAY 2
RECALL: Trigonometric Ratios
(don’t need to write)
SOH – CAH – TOA
Solving with a calculator:
Find the value of x to the nearest tenth.
sin(30) =
0.5
7sin(65) = 6.3
Solving (x in numerator - MULTIPLY)
Round to the tenth
x
cos(32) =
13
x
sin(29) =
25

13cos(32) = x
x = 11.0

25sin(29) = x
x = 12.1
Solving (x in denominator - DIVIDE)
17
tan(75) =
x

17
=x
tan(75)
x = 4.6
32
cos(56) =
x

32
=x
cos(56)
x = 57.2
TWAP 
Find the value of the missing variable to the nearest tenth.
1.9
3.8
Solving for x as angleINVERSE!! Use the 2nd key to get to sin-1
Watch me first! ROUND TO THE WHOLE DEGREE
17
sin(x) =
25

æ 17 ö
sin ç ÷
è 25 ø
-1
x  43
5
tan(x) =
18

æ 5ö
tan ç ÷ = x
è 18 ø
-1
x  16
TOO
• What is the measure of angle X to the nearest degree?
 37
 41
Homework
Sine, Cosine, Tangent Ratios – Worksheet #2