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Finding the Fourth Proportional to 83.88, 115.56 and 78.48

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Solution

The fourth proportional to 83.88, 115.56 and 78.48 is: 108.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    83.88 : 115.56 = 78.48 : x
  2. Step 2: Convert to fraction form
    83.88/115.56 = 78.48/x
  3. Step 3: Cross multiply
    83.88x = 115.56 × 78.48
  4. Step 4: Simplify right side
    83.88x = 9,069.15
  5. Step 5: Solve for x
    x = 9,069.15/83.88
  6. Step 6: Final answer
    x = 108.12

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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.