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Finding the Fourth Proportional to 102.20, 141.09 and 77.75

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Solution

The fourth proportional to 102.20, 141.09 and 77.75 is: 107.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.20 : 141.09 = 77.75 : x
  2. Step 2: Convert to fraction form
    102.20/141.09 = 77.75/x
  3. Step 3: Cross multiply
    102.20x = 141.09 × 77.75
  4. Step 4: Simplify right side
    102.20x = 10,969.75
  5. Step 5: Solve for x
    x = 10,969.75/102.20
  6. Step 6: Final answer
    x = 107.34

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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.