Trigonometry
21 . E Draw a triangle and use SOHCAHTOA to label the known sides: leg MN is 3, and
hypotenuse LM is 8. Use the Pythagorean theorem to determine the third side: LN^2 + 3^2 = 8^2 ,
so LN = eliminating (B) and (D). Since sin = , sin M = . Choice
(A) gives cos M, and (C) gives tan M.
23 . A Since no diagram is provided, make your own. The triangle will look something like this:
You can solve this question on your calculator, but that will give you a decimal. Based on the
formatting of the answer choices, it is easier to figure out the length of BC. Because this is a
45-45-90 triangle with ratios 1:1: , BC is 3 . Since cosine is defined as ,
cos ABC = , which simplifies to . Therefore, (A) is correct.
25 . C Since no diagram is provided, make your own. The figure will look something like this:
