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Finding the Fourth Proportional to 102.20, 140.90 and 71.15

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Solution

The fourth proportional to 102.20, 140.90 and 71.15 is: 98.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.20 : 140.90 = 71.15 : x
  2. Step 2: Convert to fraction form
    102.20/140.90 = 71.15/x
  3. Step 3: Cross multiply
    102.20x = 140.90 × 71.15
  4. Step 4: Simplify right side
    102.20x = 10,023.97
  5. Step 5: Solve for x
    x = 10,023.97/102.20
  6. Step 6: Final answer
    x = 98.09

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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.