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Finding the Third Proportional to 31.38 and 72.80

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Solution

The third proportional to 31.38 and 72.80 is: 168.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.38 : 72.80 = 72.80 : x
  2. Step 2: Convert to fraction form
    31.38/72.80 = 72.80/x
  3. Step 3: Cross multiply
    31.38x = 72.80 × 72.80
  4. Step 4: Simplify right side
    31.38x = 5,299.39
  5. Step 5: Solve for x
    x = 5,299.39/31.38
  6. Step 6: Final answer
    x = 168.90

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Why These Related Problems?

These problems maintain the same ratio (2.32) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.