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Finding the Fourth Proportional to 424.20, 631.59 and 421.80

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Solution

The fourth proportional to 424.20, 631.59 and 421.80 is: 628.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    424.20 : 631.59 = 421.80 : x
  2. Step 2: Convert to fraction form
    424.20/631.59 = 421.80/x
  3. Step 3: Cross multiply
    424.20x = 631.59 × 421.80
  4. Step 4: Simplify right side
    424.20x = 266,404.66
  5. Step 5: Solve for x
    x = 266,404.66/424.20
  6. Step 6: Final answer
    x = 628.02

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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.