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Finding the Fourth Proportional to 102.15, 140.87 and 99.92

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Solution

The fourth proportional to 102.15, 140.87 and 99.92 is: 137.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.15 : 140.87 = 99.92 : x
  2. Step 2: Convert to fraction form
    102.15/140.87 = 99.92/x
  3. Step 3: Cross multiply
    102.15x = 140.87 × 99.92
  4. Step 4: Simplify right side
    102.15x = 14,074.53
  5. Step 5: Solve for x
    x = 14,074.53/102.15
  6. Step 6: Final answer
    x = 137.78

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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.