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Finding the Fourth Proportional to 616.80, 925.20 and 421.86

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Solution

The fourth proportional to 616.80, 925.20 and 421.86 is: 632.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    616.80 : 925.20 = 421.86 : x
  2. Step 2: Convert to fraction form
    616.80/925.20 = 421.86/x
  3. Step 3: Cross multiply
    616.80x = 925.20 × 421.86
  4. Step 4: Simplify right side
    616.80x = 390,304.87
  5. Step 5: Solve for x
    x = 390,304.87/616.80
  6. Step 6: Final answer
    x = 632.79

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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.