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Finding the Fourth Proportional to 641.20, 961.80 and 397.80

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Solution

The fourth proportional to 641.20, 961.80 and 397.80 is: 596.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    641.20 : 961.80 = 397.80 : x
  2. Step 2: Convert to fraction form
    641.20/961.80 = 397.80/x
  3. Step 3: Cross multiply
    641.20x = 961.80 × 397.80
  4. Step 4: Simplify right side
    641.20x = 382,604.04
  5. Step 5: Solve for x
    x = 382,604.04/641.20
  6. Step 6: Final answer
    x = 596.70

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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.