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Finding the Fourth Proportional to 102.13, 140.94 and 78.77

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Solution

The fourth proportional to 102.13, 140.94 and 78.77 is: 108.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.13 : 140.94 = 78.77 : x
  2. Step 2: Convert to fraction form
    102.13/140.94 = 78.77/x
  3. Step 3: Cross multiply
    102.13x = 140.94 × 78.77
  4. Step 4: Simplify right side
    102.13x = 11,102.20
  5. Step 5: Solve for x
    x = 11,102.20/102.13
  6. Step 6: Final answer
    x = 108.71

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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.