What is the unknown side length

x = 5

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

to Right  

Equality Properties

Multiplication Property of EqualityDivision Property of EqualityAddition Property of EqualitySubtraction Property of Equality

Trigonometry

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

a is a legb is another legc is the hypotenuse

Step-by-step explanation:

Step 1: Identify Variables

Leg a = x

Leg b = 12

Hypotenuse c = 13

Step 2: Solve for x

Substitute in variables [Pythagorean Theorem]:                                          x² + 12² = 13²Evaluate exponents:                                                                                       x² + 144 = 169[Subtraction Property of Equality] Subtract 144 on both sides:                  x² = 25[Equality Property] Square root both sides:                                                  x = 5