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Finding the Fourth Proportional to 87.20, 130.92 and 77.72

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Solution

The fourth proportional to 87.20, 130.92 and 77.72 is: 116.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.20 : 130.92 = 77.72 : x
  2. Step 2: Convert to fraction form
    87.20/130.92 = 77.72/x
  3. Step 3: Cross multiply
    87.20x = 130.92 × 77.72
  4. Step 4: Simplify right side
    87.20x = 10,175.10
  5. Step 5: Solve for x
    x = 10,175.10/87.20
  6. Step 6: Final answer
    x = 116.69

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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.