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Finding the Fourth Proportional to 83.72, 124.92 and 77.68

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Solution

The fourth proportional to 83.72, 124.92 and 77.68 is: 115.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    83.72 : 124.92 = 77.68 : x
  2. Step 2: Convert to fraction form
    83.72/124.92 = 77.68/x
  3. Step 3: Cross multiply
    83.72x = 124.92 × 77.68
  4. Step 4: Simplify right side
    83.72x = 9,703.79
  5. Step 5: Solve for x
    x = 9,703.79/83.72
  6. Step 6: Final answer
    x = 115.91

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.