Answer:
x ≈ 41.4°
General Formulas and Concepts:
Pre-Algebra
Order of Operations: BPEMDAS
- Brackets
- Parenthesis
- Exponents
- Multiplication
- Division
- Addition
- Subtraction
Equality Properties
- Multiplication Property of Equality
- Division Property of Equality
- Addition Property of Equality
- Subtract Property of Equality
Pre-Calculus
- Law of Cosines: c² = a² + b² - 2(a)(b)cosC°
Step-by-step explanation:
Step 1: Identify Variables
C° = x°
c = 12
a = 15
b = 18
Step 2: Solve for x
- Substitute [LC]: 12² = 15² + 18² - 2(15)(18)cosx°
- Exponents: 144 = 225 + 324 - 2(15)(18)cosx°
- Add: 144 = 549 - 2(15)(18)cosx°
- Multiply: 144 = 549 - 540cosx°
- Isolate x term: -405 = -540cosx°
- Isolate x term: 3/4 = cosx°
- Isolate x: cos⁻¹(3/4) = x°
- Evaluate: x = 41.4096°
- Round: x ≈ 41.4°