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Finding the Fourth Proportional to 87.20, 130.90 and 51.15

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Solution

The fourth proportional to 87.20, 130.90 and 51.15 is: 76.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.20 : 130.90 = 51.15 : x
  2. Step 2: Convert to fraction form
    87.20/130.90 = 51.15/x
  3. Step 3: Cross multiply
    87.20x = 130.90 × 51.15
  4. Step 4: Simplify right side
    87.20x = 6,695.54
  5. Step 5: Solve for x
    x = 6,695.54/87.20
  6. Step 6: Final answer
    x = 76.78

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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.