Question

2-3 reteach to build unde parallel lines and triangle angl 1. use the diagrams to fill in the blanks. interior angle measures m∠a + m∠b + m∠c = 180° + m∠b + = 180° m∠b + = 180° m∠b =

Explanation:

Step1: Substitute known angles

Given $m\angle A = 54^{\circ}$ and $m\angle C=48^{\circ}$, substitute into $m\angle A + m\angle B + m\angle C = 180^{\circ}$. So we have $54^{\circ}+m\angle B + 48^{\circ}=180^{\circ}$.

Step2: Combine like - terms

$54^{\circ}+48^{\circ}+m\angle B=180^{\circ}$, which simplifies to $102^{\circ}+m\angle B = 180^{\circ}$.

Step3: Solve for $m\angle B$

Subtract $102^{\circ}$ from both sides of the equation: $m\angle B=180^{\circ}- 102^{\circ}$.

Answer:

$m\angle B = 78^{\circ}$