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Finding the Fourth Proportional to 458.38, 684.19 and 421.78

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Solution

The fourth proportional to 458.38, 684.19 and 421.78 is: 629.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    458.38 : 684.19 = 421.78 : x
  2. Step 2: Convert to fraction form
    458.38/684.19 = 421.78/x
  3. Step 3: Cross multiply
    458.38x = 684.19 × 421.78
  4. Step 4: Simplify right side
    458.38x = 288,577.66
  5. Step 5: Solve for x
    x = 288,577.66/458.38
  6. Step 6: Final answer
    x = 629.56

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.