Question

given that (mangle a = 51^{circ}), find (mangle b). (mangle b=) o resources watch it ebook

Explanation:

Step1: Note angle - relationship

Angles $a$ and $b$ are supplementary, so $m\angle a+m\angle b = 180^{\circ}$.

Step2: Solve for $m\angle b$

$m\angle b=180^{\circ}-m\angle a$.
Substitute $m\angle a = 51^{\circ}$ into the equation: $m\angle b=180 - 51$.

Answer:

$129$