Question

On a math test the students are given a right triangle. One of the acute angles has a measure of 31°. One student says that the measure of the other acute angle is 149°. What is the measure of the other acute​ angle? What error might the student have​ made?

Answer 1

Explanation:

Acute angles can't be over 90°

Answer 2

The measure of the other acute angle is 59 degrees

The mistake the student has made is subtracting 31 degrees from 180 degrees (the total amount of degrees a triangle has)

The student needed to realize
A) acute angles are less than 80 degrees
B) he needed to subtract 90 from 180 as well.

180 - 90 (from the right triangle) - 31 = 59