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Finding the Fourth Proportional to 101.50, 139.92 and 87.61

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Solution

The fourth proportional to 101.50, 139.92 and 87.61 is: 120.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    101.50 : 139.92 = 87.61 : x
  2. Step 2: Convert to fraction form
    101.50/139.92 = 87.61/x
  3. Step 3: Cross multiply
    101.50x = 139.92 × 87.61
  4. Step 4: Simplify right side
    101.50x = 12,258.39
  5. Step 5: Solve for x
    x = 12,258.39/101.50
  6. Step 6: Final answer
    x = 120.77

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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.