SOLUTION: how do i use sin cos and tan on the calculator and how can i find the side length and angle measure of a triangle with line AC= 21in line BC=15ins and its a right triangle. I have

Algebra ->  Trigonometry-basics -> SOLUTION: how do i use sin cos and tan on the calculator and how can i find the side length and angle measure of a triangle with line AC= 21in line BC=15ins and its a right triangle. I have       Log On


   

Question 140378: how do i use sin cos and tan on the calculator and how can i find the side length and angle measure of a triangle with line AC= 21in line BC=15ins and its a right triangle. I have a algebra 1 text book on page 637 # 27
Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
1) On the TI-86 calculator, you would enter the number of degrees in the keypad, then push the SIN key for the sine of that angle, or the COS key for the cosine of the angle, or the TAN key for the tangent of the angle.
2) To find the length of the missing side, side c (hypotenuse) in this problem, you can use the Pythagorean theorem: c+=+sqrt%28a%5E2%2Bb%5E2%29
c+=+sqrt%2821%5E2%2B15%5E2%29
c+=+sqrt%28441%2B225%29
c+=+sqrt%28666%29
c+=+25.8 to the nearest tenth.
For the angles, you need only to find one of the missing angles.
You can use the arctangent (AKA inverse tangent) function to find either angle A or angle B. Let's find angle A.
tan%28A%29+=+15%2F21
A+=+Arctan%2815%2F21%29 Read this as "A is the angle whose tangent is 15/21"
Note: The arctan is shown as tan^(-1) on your calculator.
A+=+36degrees (to the nearest degree).
Angle B = 90-A
B = 90-36
B = 54 degrees (to the nearest degree).