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Finding the Fourth Proportional to 458.61, 687.89 and 215.31

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Solution

The fourth proportional to 458.61, 687.89 and 215.31 is: 322.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    458.61 : 687.89 = 215.31 : x
  2. Step 2: Convert to fraction form
    458.61/687.89 = 215.31/x
  3. Step 3: Cross multiply
    458.61x = 687.89 × 215.31
  4. Step 4: Simplify right side
    458.61x = 148,108.52
  5. Step 5: Solve for x
    x = 148,108.52/458.61
  6. Step 6: Final answer
    x = 322.95

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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.