Answer:
43°
Step-by-step explanation:
Since we know that ∠ADC, which is the sum of ∠ADB and ∠BDC, is 112, we can solve for x:
112 = 6x + 7 + 12x - 3
112 = 18x +4
112 - 4 = 18x → 108 = 18x
108/18 = x → 6 = x.
Now, we can substitute 6 for x in the equation for ∠ADB to get the answer:
6(6) + 7 ⇒ 36 + 7 ⇒ 43°.
Hope this helps! Have a nice day!
