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Finding the Fourth Proportional to 641.71, 961.52 and 421.87

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Solution

The fourth proportional to 641.71, 961.52 and 421.87 is: 632.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    641.71 : 961.52 = 421.87 : x
  2. Step 2: Convert to fraction form
    641.71/961.52 = 421.87/x
  3. Step 3: Cross multiply
    641.71x = 961.52 × 421.87
  4. Step 4: Simplify right side
    641.71x = 405,636.44
  5. Step 5: Solve for x
    x = 405,636.44/641.71
  6. Step 6: Final answer
    x = 632.12

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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.