Question

17 if ( mangle a = 38^{circ} ) then ( mangle b=)______.

Explanation:

Step1: Use the property of adjacent angles on a straight line

Adjacent angles on a straight line sum to \(180^{\circ}\). \(\angle A\) and \(\angle B\) are adjacent angles on a straight line.

Step2: Calculate \(m\angle B\)

We know that \(m\angle A + m\angle B=180^{\circ}\). Given \(m\angle A = 38^{\circ}\), then \(m\angle B=180^{\circ}-m\angle A\).
Substitute \(m\angle A = 38^{\circ}\) into the formula: \(m\angle B = 180^{\circ}-38^{\circ}\).
\(m\angle B=142^{\circ}\)

Answer:

\(142^{\circ}\)