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Finding the Fourth Proportional to 458.39, 686.91 and 420.68

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Solution

The fourth proportional to 458.39, 686.91 and 420.68 is: 630.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    458.39 : 686.91 = 420.68 : x
  2. Step 2: Convert to fraction form
    458.39/686.91 = 420.68/x
  3. Step 3: Cross multiply
    458.39x = 686.91 × 420.68
  4. Step 4: Simplify right side
    458.39x = 288,969.30
  5. Step 5: Solve for x
    x = 288,969.30/458.39
  6. Step 6: Final answer
    x = 630.40

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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.