Question

in the figure, m∠7 = 100°. find the measure of ∠2.

Explanation:

Step1: Identify angle - pair relationship

$\angle7$ and $\angle8$ are a linear - pair.
$m\angle7 + m\angle8=180^{\circ}$

Step2: Calculate $m\angle8$

Since $m\angle7 = 100^{\circ}$, then $m\angle8=180^{\circ}-100^{\circ}=80^{\circ}$

Step3: Use corresponding - angles property

$\angle2$ and $\angle8$ are corresponding angles.
$m\angle2 = m\angle8$

Answer:

$80$