# SAT Math Multiple Choice Question 990: Answer and Explanation

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**Question: 990**

**10.** Right triangle *ABC* has side lengths 7, 24, and 25. If ∠*B* is the second-largest interior angle of the triangle, what is the cosine of ∠*B*?

- A.
- B.
- C.
- D.

**Correct Answer:** A

**Explanation:**

**A**

**Difficulty:** Easy

**Category:** Additional Topics in Math / Trigonometry

**Strategic Advice:** The second-largest angle of a triangle must be opposite the second-longest side. Knowing this allows you to draw a sketch and use SOH CAH TOA to find the cosine of the indicated angle.

**Getting to the Answer:** Draw a quick sketch of a right triangle with one leg that is considerably longer than the other. (The hypotenuse of a right triangle is always the longest side.) The sketch should help you see that ∠*B* is across from the side labeled 24:

By SOH CAH TOA, cos ∠*B* =, which is (A).