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Finding the Fourth Proportional to 83.71, 115.18 and 72.78

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Solution

The fourth proportional to 83.71, 115.18 and 72.78 is: 100.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    83.71 : 115.18 = 72.78 : x
  2. Step 2: Convert to fraction form
    83.71/115.18 = 72.78/x
  3. Step 3: Cross multiply
    83.71x = 115.18 × 72.78
  4. Step 4: Simplify right side
    83.71x = 8,382.80
  5. Step 5: Solve for x
    x = 8,382.80/83.71
  6. Step 6: Final answer
    x = 100.14

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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.