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Finding the Fourth Proportional to 87.76, 130.88 and 86.72

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Solution

The fourth proportional to 87.76, 130.88 and 86.72 is: 129.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.76 : 130.88 = 86.72 : x
  2. Step 2: Convert to fraction form
    87.76/130.88 = 86.72/x
  3. Step 3: Cross multiply
    87.76x = 130.88 × 86.72
  4. Step 4: Simplify right side
    87.76x = 11,349.91
  5. Step 5: Solve for x
    x = 11,349.91/87.76
  6. Step 6: Final answer
    x = 129.33

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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.