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Finding the Fourth Proportional to 78.86, 109.25 and 76.97

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Solution

The fourth proportional to 78.86, 109.25 and 76.97 is: 106.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.86 : 109.25 = 76.97 : x
  2. Step 2: Convert to fraction form
    78.86/109.25 = 76.97/x
  3. Step 3: Cross multiply
    78.86x = 109.25 × 76.97
  4. Step 4: Simplify right side
    78.86x = 8,409.67
  5. Step 5: Solve for x
    x = 8,409.67/78.86
  6. Step 6: Final answer
    x = 106.64

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.