Respuesta :

Space

Answer:

a = 12

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

  1. Brackets
  2. Parenthesis
  3. Exponents
  4. Multiplication
  5. Division
  6. Addition
  7. Subtraction
  • Left to Right  

Equality Properties

  • Multiplication Property of Equality
  • Division Property of Equality
  • Addition Property of Equality
  • Subtraction Property of Equality

Trigonometry

[Right Triangles Only] Pythagorean Theorem: a² + b² = c²

  • a is a leg
  • b is another leg
  • c is the hypotenuse

Step-by-step explanation:

Step 1: Define

Identify variables

a = a

b = 9

c = 15

Step 2: Solve for a

  1. Substitute in variables [Pythagorean Theorem]:                                            a² + 9² = 15²
  2. Evaluate exponents:                                                                                         a² + 81 = 225
  3. [Subtraction Property of Equality] Subtract 81 on both sides:                       a² = 144
  4. [Equality Property] Square root both sides:                                                    a = 12