Explanation:
question 1
angle DBA=90°, meaning to find m<D you have to add 90+38 then subtract by 180, because ABD is a triangle
90+18+m<D=180
108+m<D=180
m<D=180-108
=72°
question 2
m<D again in this case angle ABD is also 90
m<D=180-(90+48)
=180-138
=42°
I hope this helps