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Finding the Fourth Proportional to 458.20, 687.30 and 398.80

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Solution

The fourth proportional to 458.20, 687.30 and 398.80 is: 598.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    458.20 : 687.30 = 398.80 : x
  2. Step 2: Convert to fraction form
    458.20/687.30 = 398.80/x
  3. Step 3: Cross multiply
    458.20x = 687.30 × 398.80
  4. Step 4: Simplify right side
    458.20x = 274,095.24
  5. Step 5: Solve for x
    x = 274,095.24/458.20
  6. Step 6: Final answer
    x = 598.20

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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.