Question

the terminal angle of \\(m\angle def\\) is \\(139^\circ\\). what is the measure of its reference angle?

Explanation:

Identify the quadrant of the given angle

$$ 90^\circ < 139^\circ < 180^\circ \implies \text{Quadrant II} $$

Apply the reference angle formula for Quadrant II

$$ \theta' = 180^\circ - \theta $$

$$ \theta' = 180^\circ - 139^\circ $$

Calculate the final measure

$$ \theta' = 41^\circ $$

Answer:

The terminal angle of m\(\angle\)DEF is \(139^\circ\). What is the measure of its reference angle? <blank>\(41^\circ\)</blank>