Question

estimate the measure of this angle within 15°.

Explanation:

Step1: Compare to known angles

A right angle is $90^\circ$, this angle is much smaller. A $30^\circ$ angle is a narrow acute angle, this is slightly wider.

Step2: Apply 15° tolerance

Estimate a value between $20^\circ$ and $50^\circ$; a reasonable midpoint is $30^\circ$ to $40^\circ$.

Answer:

$\boldsymbol{30^\circ}$ (or any value between $20^\circ$ and $45^\circ$ is acceptable within the 15° tolerance)