Download 4.3A Right Triangle Trig

Trig./Pre-Calc
4.3A Right Triangle Trigonometry
Example #1
Find the exact value of the six trigonometric functions of the angle  given in the
accompanying figure. (Use the Pythagorean Theorem to find the third side of the angle.)
4

6
Example #2
Sketch a right triangle corresponding to the trigonometric function of the acute angle .
Use the Pythagorean Theorem to determine the third side and then find the other five
trigonometric functions of .
a) tan  =
5
2
b) sin  
5
6
Example #3
Evaluate the trigonometric function by constructing an appropriate triangle for the special
angle.

a)
cos 60°
b)
tan
6
Example #4 Complete the identity.
a) sin  
1
b) sin( 90    ) 
Example #5
Use the given functional values and trigonometric identities (including the relationship
between a trigonometric function and its co-function of a complementary angle) to find
the trigonometric functions.
sin 60 
3
,
2
(a) tan 60 
cos 60 
1
2
(b) sin 30 
(c) cos 30 
(d) cot 60 
Example #6 Review Problems.
a) Solve for x.
1
1
10

 2
x3 x3 x 9
b) Solve for x by extracting square roots. (2x-1)2 = 12
4-3A Pg. 284 #2-44 even (Note: on # 6 and #8, use the first triangle only)