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Finding the Fourth Proportional to 78.78, 108.08 and 76.65

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Solution

The fourth proportional to 78.78, 108.08 and 76.65 is: 105.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.78 : 108.08 = 76.65 : x
  2. Step 2: Convert to fraction form
    78.78/108.08 = 76.65/x
  3. Step 3: Cross multiply
    78.78x = 108.08 × 76.65
  4. Step 4: Simplify right side
    78.78x = 8,283.54
  5. Step 5: Solve for x
    x = 8,283.54/78.78
  6. Step 6: Final answer
    x = 105.15

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.