Answer:
81°
Step-by-step explanation:
∠ABC= 121°
∠ABD= 4*15°+21°= 81°
81
ABD + BDC = ABC
4x+21 + 3x-5 =121
Combine like terms
7x +16 = 121
Subtract 16 from each side
7x+16-16 = 121-16
7x =105
Divide each side by 7
7x/7 =105/7
x=15
We want to find ABD
ABD = 4x+21
= 4*15+21
= 60+21
=81
