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Finding the Fourth Proportional to 87.65, 131.40 and 61.89

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Solution

The fourth proportional to 87.65, 131.40 and 61.89 is: 92.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.65 : 131.40 = 61.89 : x
  2. Step 2: Convert to fraction form
    87.65/131.40 = 61.89/x
  3. Step 3: Cross multiply
    87.65x = 131.40 × 61.89
  4. Step 4: Simplify right side
    87.65x = 8,132.35
  5. Step 5: Solve for x
    x = 8,132.35/87.65
  6. Step 6: Final answer
    x = 92.78

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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.