Question

what is the measure of the missing angle? m∠abc = ?° enter the number of degrees. 45°

Explanation:

Step1: Use the property of a straight - line angle

A straight - line angle measures \(180^{\circ}\). So, \(m\angle ABC+m\angle CBD = 180^{\circ}\).

Step2: Solve for \(m\angle ABC\)

Let \(x=m\angle ABC\). We know that \(m\angle CBD = 45^{\circ}\). Then \(x+45^{\circ}=180^{\circ}\). Subtract \(45^{\circ}\) from both sides: \(x=180^{\circ}- 45^{\circ}\).

Answer:

\(135\)