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Finding the Fourth Proportional to 458.20, 687.30 and 407.80

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Solution

The fourth proportional to 458.20, 687.30 and 407.80 is: 611.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    458.20 : 687.30 = 407.80 : x
  2. Step 2: Convert to fraction form
    458.20/687.30 = 407.80/x
  3. Step 3: Cross multiply
    458.20x = 687.30 × 407.80
  4. Step 4: Simplify right side
    458.20x = 280,280.94
  5. Step 5: Solve for x
    x = 280,280.94/458.20
  6. Step 6: Final answer
    x = 611.70

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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.