Question

error analysis on a math test the students are given a right triangle. one of the acute angles has a measure of 42°. one student says that the measure of the other acute angle is 138°. what is the measure of the other acute angle? what error might the student have made? the measure of the other acute angle is °

Explanation:

Step1: Recall angle - sum property of a triangle

The sum of the interior angles of a triangle is 180°. In a right - triangle, one angle is 90°.

Step2: Let the unknown acute angle be \(x\)

We know that \(90^{\circ}+42^{\circ}+x = 180^{\circ}\).

Step3: Solve for \(x\)

\[

$$\begin{align*} x&=180^{\circ}-(90^{\circ} + 42^{\circ})\\ x&=180^{\circ}-132^{\circ}\\ x& = 48^{\circ} \end{align*}$$

\]
The error the student might have made is subtracting 42° from 90° instead of subtracting the sum of 90° and 42° from 180°.

Answer:

48