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Finding the Fourth Proportional to 87.31, 120.10 and 77.32

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Solution

The fourth proportional to 87.31, 120.10 and 77.32 is: 106.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.31 : 120.10 = 77.32 : x
  2. Step 2: Convert to fraction form
    87.31/120.10 = 77.32/x
  3. Step 3: Cross multiply
    87.31x = 120.10 × 77.32
  4. Step 4: Simplify right side
    87.31x = 9,285.14
  5. Step 5: Solve for x
    x = 9,285.14/87.31
  6. Step 6: Final answer
    x = 106.35

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.