Law of sines and cosines. (TRIANGLES) TRIG!

2. Using a scientific calculator, find the cos 36 degrees.
A. .9421
B. .8090
C. .7113
D. .6591

3. In the right triangle ABC, angle C equals 90 degrees. If angle B is 63 degrees, what is the measure of angle A?
A. 27 degrees
B. 37 degrees
C. 47 degrees
D. 57 degrees

4. When using right triangle trigonometry, the ratio of adjacent side/hypotenuse is named what?
A. Sine
B. Cosine
C. Tangent

8. Solve the trig equation for which x is the missing side of a right triangle.
sin 34 degrees =x/7
A. 3.2
B.3.9
C. 4.7
D. 8.3

10. Using a scientific calculator, find the meausre of the angle whose tangent value is 1.2799
A. 40 degrees
B. 47 degrees
C. 52 degrees
D. 60 degrees
Thanks everyone.

2. B. Make sure your calculator is in degree mode (not radians) and type in cos(36.

3. A. A triangle has 180 degrees. 180 - (63 + 90) = 27.

4. B. Cosine. Remember the CAH in SOHCAHTOA. Cosine=adjacent/hypotenuse.

8. B. sin(34 degrees = x/7
Multiply both sides by 7.
7sin(34 = x
Type in 7sin(34 on your calculator to get the value of x. It is approximately 3.9.

10. C. tan(x = 1.2799
Use the arctan operator, which looks like this: tan^-1. It basically "undoes" the tangent part of tan(x so you end up with just x.
x = tan^-1(1.2799
x = approximately 52 degrees

2) cos(36°) is approximately 0.8090. Answer choice B.
3) The sum of the measures of the angles of a triangle is always 180°.
So, then 180° = 90° + 63° +x°.
180 = 153 + x
27 = x
Answer choice A.
4) Adjacent / Hypotenuse is also known as cosine.
Answer choice B.
8) sin(34°) = x / 7
7(sin(34°)) = x
x is approximately 3.914
Answer choice B.
10) tan(x) = 1.2799
x = arctan(1.2799)
x is approximately 52 degrees.
Answer choice C.

I hope this helps!

2.) B

3.) 180 - (90 + 63) = 27 degrees

4) B

8.) x = 7*sin(34) = 3.9

10) arctan(1.2799) = 52 degrees