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Finding the Fourth Proportional to 638.29, 956.17 and 421.21

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Solution

The fourth proportional to 638.29, 956.17 and 421.21 is: 630.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    638.29 : 956.17 = 421.21 : x
  2. Step 2: Convert to fraction form
    638.29/956.17 = 421.21/x
  3. Step 3: Cross multiply
    638.29x = 956.17 × 421.21
  4. Step 4: Simplify right side
    638.29x = 402,748.37
  5. Step 5: Solve for x
    x = 402,748.37/638.29
  6. Step 6: Final answer
    x = 630.98

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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.