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Finding the Fourth Proportional to 87.30, 129.96 and 86.85

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Solution

The fourth proportional to 87.30, 129.96 and 86.85 is: 129.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.30 : 129.96 = 86.85 : x
  2. Step 2: Convert to fraction form
    87.30/129.96 = 86.85/x
  3. Step 3: Cross multiply
    87.30x = 129.96 × 86.85
  4. Step 4: Simplify right side
    87.30x = 11,287.03
  5. Step 5: Solve for x
    x = 11,287.03/87.30
  6. Step 6: Final answer
    x = 129.29

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.