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Finding the Fourth Proportional to 661.33, 991.98 and 641.28

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Solution

The fourth proportional to 661.33, 991.98 and 641.28 is: 961.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.33 : 991.98 = 641.28 : x
  2. Step 2: Convert to fraction form
    661.33/991.98 = 641.28/x
  3. Step 3: Cross multiply
    661.33x = 991.98 × 641.28
  4. Step 4: Simplify right side
    661.33x = 636,140.65
  5. Step 5: Solve for x
    x = 636,140.65/661.33
  6. Step 6: Final answer
    x = 961.91

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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.