Home / 624.20-861.30-391.32

Finding the Fourth Proportional to 624.20, 861.30 and 391.32

Calculator

Solution

The fourth proportional to 624.20, 861.30 and 391.32 is: 539.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    624.20 : 861.30 = 391.32 : x
  2. Step 2: Convert to fraction form
    624.20/861.30 = 391.32/x
  3. Step 3: Cross multiply
    624.20x = 861.30 × 391.32
  4. Step 4: Simplify right side
    624.20x = 337,043.92
  5. Step 5: Solve for x
    x = 337,043.92/624.20
  6. Step 6: Final answer
    x = 539.97

Related Problems

Find fourth proportional to 312.10, 430.65 and 195.66
Half scale
Find fourth proportional to 1,248.39, 1,722.60 and 782.64
Double scale
Find fourth proportional to 625.20, 862.68 and 392.32
Similar ratio
Find fourth proportional to 936.29, 1,291.95 and 586.98
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.