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Finding the Fourth Proportional to 83.68, 115.20 and 72.70

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Solution

The fourth proportional to 83.68, 115.20 and 72.70 is: 100.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    83.68 : 115.20 = 72.70 : x
  2. Step 2: Convert to fraction form
    83.68/115.20 = 72.70/x
  3. Step 3: Cross multiply
    83.68x = 115.20 × 72.70
  4. Step 4: Simplify right side
    83.68x = 8,375.04
  5. Step 5: Solve for x
    x = 8,375.04/83.68
  6. Step 6: Final answer
    x = 100.08

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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.