Question

m∠abc = 45°
what type of angle is it?
obtuse
straight
right
acute

Explanation:

Step1: Define angle types

Acute: $<90^\circ$; right: $=90^\circ$; obtuse: $90^\circ

Step2: Compare $45^\circ$ with $90^\circ$

$45^\circ<90^\circ$, so acute.

Answer:

D. acute