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Finding the Third Proportional to 139.78 and 220.92

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Solution

The third proportional to 139.78 and 220.92 is: 349.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.78 : 220.92 = 220.92 : x
  2. Step 2: Convert to fraction form
    139.78/220.92 = 220.92/x
  3. Step 3: Cross multiply
    139.78x = 220.92 × 220.92
  4. Step 4: Simplify right side
    139.78x = 48,806.47
  5. Step 5: Solve for x
    x = 48,806.47/139.78
  6. Step 6: Final answer
    x = 349.16

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Why These Related Problems?

These problems maintain the same ratio (1.58) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.