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Finding the Fourth Proportional to 421.68, 628.80 and 392.46

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Solution

The fourth proportional to 421.68, 628.80 and 392.46 is: 585.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.68 : 628.80 = 392.46 : x
  2. Step 2: Convert to fraction form
    421.68/628.80 = 392.46/x
  3. Step 3: Cross multiply
    421.68x = 628.80 × 392.46
  4. Step 4: Simplify right side
    421.68x = 246,778.85
  5. Step 5: Solve for x
    x = 246,778.85/421.68
  6. Step 6: Final answer
    x = 585.23

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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.