Question

step angle reason
1 $m\angle adb = 98^{\circ}$ given
2 $m\angle b = 45^{\circ}$ given
3 $m\angle bad = 37^{\circ}$ sum of angles in a triangle
try $m\angle\square=\square^{\circ}$ select a reason

Explanation:

Step1: Find the adjacent angle to ∠ADB

Since ∠ADB and ∠ADC form a linear pair (they are adjacent and supplementary), we know that \(m\angle ADB + m\angle ADC=180^{\circ}\).
Given \(m\angle ADB = 98^{\circ}\), then \(m\angle ADC=180^{\circ}-98^{\circ}\).

Step2: Calculate the value of \(m\angle ADC\)

\(m\angle ADC = 180 - 98=82^{\circ}\)

Answer:

\(m\angle ADC = 82^{\circ}\), Reason: Linear - pair (supplementary angles)