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Finding the Fourth Proportional to 78.78, 107.99 and 78.66

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Solution

The fourth proportional to 78.78, 107.99 and 78.66 is: 107.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.78 : 107.99 = 78.66 : x
  2. Step 2: Convert to fraction form
    78.78/107.99 = 78.66/x
  3. Step 3: Cross multiply
    78.78x = 107.99 × 78.66
  4. Step 4: Simplify right side
    78.78x = 8,494.49
  5. Step 5: Solve for x
    x = 8,494.49/78.78
  6. Step 6: Final answer
    x = 107.83

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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.