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Finding the Fourth Proportional to 102.40, 141.24 and 77.86

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Solution

The fourth proportional to 102.40, 141.24 and 77.86 is: 107.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.40 : 141.24 = 77.86 : x
  2. Step 2: Convert to fraction form
    102.40/141.24 = 77.86/x
  3. Step 3: Cross multiply
    102.40x = 141.24 × 77.86
  4. Step 4: Simplify right side
    102.40x = 10,997.41
  5. Step 5: Solve for x
    x = 10,997.41/102.40
  6. Step 6: Final answer
    x = 107.40

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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.