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Finding the Fourth Proportional to 102.41, 140.90 and 77.70

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Solution

The fourth proportional to 102.41, 140.90 and 77.70 is: 106.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.41 : 140.90 = 77.70 : x
  2. Step 2: Convert to fraction form
    102.41/140.90 = 77.70/x
  3. Step 3: Cross multiply
    102.41x = 140.90 × 77.70
  4. Step 4: Simplify right side
    102.41x = 10,947.54
  5. Step 5: Solve for x
    x = 10,947.54/102.41
  6. Step 6: Final answer
    x = 106.90

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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.