SOLUTION: In triangle ABC, angle C is a right angle. If sin A = 6/10, find cos A. a. 3/5 b. 3/4 c. 8/10 d. 10/8

Algebra ->  Triangles -> SOLUTION: In triangle ABC, angle C is a right angle. If sin A = 6/10, find cos A. a. 3/5 b. 3/4 c. 8/10 d. 10/8      Log On


   

Question 282047: In triangle ABC, angle C is a right angle. If sin A = 6/10, find cos A.
a. 3/5
b. 3/4
c. 8/10
d. 10/8
Found 2 solutions by Mathematicians, solver91311:
Answer by Mathematicians(84) About Me  (Show Source):
You can put this solution on YOUR website!
We know that X%5E2+%2B+Y%5E2+=+Z%5E2 where Z is the hypotenuse and X and Y are two sides of a right triangle.
For sine = Y/Z = 6/10
so we know X%5E2+%2B+6%5E2+=+10%5E2
which is X%5E2+%2B+36+=+100
which is X%5E2+=+64
which is X+=+8 since we are dealing with distance, we take the positive value for X.
We know cosine is X/Z, Z stays the same and X is 8. So your answer is 8/10 or 4/5

Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!




so:



so:



Or you could just recognize that is is just a 3:4:5 right triangle, so the sides are 6 and 8 and the hypotenuse is 10, so has to be


John