# ASVAB Mathematics Knowledge Practice: Triangles

Triangles are pretty common in real life, so you should expect to see triangle problems on the Mathematics Knowledge subtest on the ASVAB. In the following practice questions, you have to find an interior angle of a triangle, and then use algebra to solve for *x* in a congruent triangle.

## Practice questions

## Answers and explanations

- The correct answer is
**Choice (B).**

The sum of all angles in a triangle is 180 degrees, so fill in the values you know using*A*+*B*+*C*= 180 degrees and let*x*represent the angle you don’t know (note that angle*A*is a right angle, so it’s 90 degrees): - The correct answer is
**Choice (A).**

The triangle has two congruent sides (that’s what the hash marks represent). That means the two sides are equal. Set their values equal to each other and solve for*x*: