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Finding the Fourth Proportional to 83.79, 115.37 and 78.12

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Solution

The fourth proportional to 83.79, 115.37 and 78.12 is: 107.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    83.79 : 115.37 = 78.12 : x
  2. Step 2: Convert to fraction form
    83.79/115.37 = 78.12/x
  3. Step 3: Cross multiply
    83.79x = 115.37 × 78.12
  4. Step 4: Simplify right side
    83.79x = 9,012.31
  5. Step 5: Solve for x
    x = 9,012.31/83.79
  6. Step 6: Final answer
    x = 107.56

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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.