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Finding the Fourth Proportional to 102.20, 140.71 and 91.55

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Solution

The fourth proportional to 102.20, 140.71 and 91.55 is: 126.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.20 : 140.71 = 91.55 : x
  2. Step 2: Convert to fraction form
    102.20/140.71 = 91.55/x
  3. Step 3: Cross multiply
    102.20x = 140.71 × 91.55
  4. Step 4: Simplify right side
    102.20x = 12,882.00
  5. Step 5: Solve for x
    x = 12,882.00/102.20
  6. Step 6: Final answer
    x = 126.05

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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.