Home / 328.40-492.60-287.90

Finding the Fourth Proportional to 328.40, 492.60 and 287.90

Calculator

Solution

The fourth proportional to 328.40, 492.60 and 287.90 is: 431.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    328.40 : 492.60 = 287.90 : x
  2. Step 2: Convert to fraction form
    328.40/492.60 = 287.90/x
  3. Step 3: Cross multiply
    328.40x = 492.60 × 287.90
  4. Step 4: Simplify right side
    328.40x = 141,819.54
  5. Step 5: Solve for x
    x = 141,819.54/328.40
  6. Step 6: Final answer
    x = 431.85

Related Problems

Find fourth proportional to 164.20, 246.30 and 143.95
Half scale
Find fourth proportional to 656.80, 985.20 and 575.80
Double scale
Find fourth proportional to 329.40, 494.10 and 288.90
Similar ratio
Find fourth proportional to 492.60, 738.90 and 431.85
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.