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Finding the Fourth Proportional to 621.72, 932.31 and 390.87

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Solution

The fourth proportional to 621.72, 932.31 and 390.87 is: 586.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    621.72 : 932.31 = 390.87 : x
  2. Step 2: Convert to fraction form
    621.72/932.31 = 390.87/x
  3. Step 3: Cross multiply
    621.72x = 932.31 × 390.87
  4. Step 4: Simplify right side
    621.72x = 364,412.01
  5. Step 5: Solve for x
    x = 364,412.01/621.72
  6. Step 6: Final answer
    x = 586.14

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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.