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Finding the Fourth Proportional to 79.87, 110.28 and 78.61

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Solution

The fourth proportional to 79.87, 110.28 and 78.61 is: 108.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.87 : 110.28 = 78.61 : x
  2. Step 2: Convert to fraction form
    79.87/110.28 = 78.61/x
  3. Step 3: Cross multiply
    79.87x = 110.28 × 78.61
  4. Step 4: Simplify right side
    79.87x = 8,669.11
  5. Step 5: Solve for x
    x = 8,669.11/79.87
  6. Step 6: Final answer
    x = 108.54

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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.