Answer:
m∠B = 69°
General Formulas and Concepts:
- Order of Operations: BPEMDAS
- Complementary Angles add up to 90°
Explanation:
Step 1: Define
m∠A = (x + 9)°
m∠B = (7x - 15)°
Step 2: Set up equation
m∠A + m∠B = 90°
(x + 9)° + (7x - 15)° = 90°
Step 3: Solve for x
- Combine like terms: 8x - 6 = 90
- Add 6 to both sides: 8x = 96
- Divide both sides by 8: x = 12
Step 4: Find m∠B
- Define: m∠B = (7x - 15)°
- Substitute: m∠B = (7(12) - 15)°
- Multiply: m∠B = (84 - 15)°
- Subtract: m∠B = 69°