Answer: 28.8°
Step-by-step explanation:
∠A = 5(∠B) + 7.2°
∠B = ∠B
Since they are on a straight line, they form a linear pair (sum = 180°)
∠A + ∠B = 180°
Use Substitution:
5(∠B) + 7.2° + ∠B = 180°
Add like terms:
6(∠B) + 7.2° = 180°
Subtract 7.2° from both sides:
6(∠B) = 172.8°
Divide both sides by 6:
∠B = 28.8°
