Question

what is the measure of this angle? choose the best estimate.$80^{circ}$$100^{circ}$$45^{circ}$$130^{circ}$

Explanation:

Step1: Compare to reference angles

A right angle is $90^\circ$, this angle is smaller than $90^\circ$. Eliminate $100^\circ$ and $130^\circ$.

Step2: Distinguish remaining options

A $45^\circ$ angle is half a right angle; this angle is larger than half a right angle, so it is closer to $80^\circ$.

Answer:

80°