Question

What is the missing value in the proportion 4/5 = x/30?

A.) 6

B.) 24

C.) 37.5

D.) 29

Answer 1

`\displaystyle x = 24`

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

Explanation:

Step 1: Define

`\displaystyle (4)/(5) = (x)/(30)`

Step 2: Solve for x

1. [Multiplication Property of Equality] Cross-multiply:
   `\displaystyle 5x = 120`
2. [Division Property of Equality] Divide 5 on both sides:
   `\displaystyle x = 24`