Since line segment AD bisects angle ∠CAB, the measure of ∠CAB is equal to the sum of the measures of angles ∠BAD and ∠DAC.
Given:
- m∠BAD = 21 degrees
Since AD bisects ∠CAB, we have:
- m∠DAC = m∠BAD
Therefore:
- m∠DAC = 21 degrees
To find the measure of ∠CAB: m∠CAB = m∠BAD + m∠DAC m∠CAB = 21 degrees + 21 degrees m∠CAB = 42 degrees
Thus, the measure of ∠CAB is 42 degrees.