9514 1404 393
Answer:
70° (number in the blank at the bottom)
Step-by-step explanation:
You need to know the meaning of "complement of an angle."
Complementary angles have a sum of 90°. So, the complement of 20° is the angle that makes the total 90°. It is 70°.
The line at the bottom of the figure tells you how to work the problem. It says "the cosine of an angle is the sine of its complement." If you put numbers in this statement, it tells you ...
the cosine of 20° is the sine of 70°
So, the answer to the question at the top of the page is ...
look up the value of sin(70°) in the table
