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Finding the Fourth Proportional to 421.40, 628.46 and 385.97

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Solution

The fourth proportional to 421.40, 628.46 and 385.97 is: 575.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.40 : 628.46 = 385.97 : x
  2. Step 2: Convert to fraction form
    421.40/628.46 = 385.97/x
  3. Step 3: Cross multiply
    421.40x = 628.46 × 385.97
  4. Step 4: Simplify right side
    421.40x = 242,563.08
  5. Step 5: Solve for x
    x = 242,563.08/421.40
  6. Step 6: Final answer
    x = 575.61

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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.