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Finding the Third Proportional to 639.06 and 1,378.81

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Solution

The third proportional to 639.06 and 1,378.81 is: 2,974.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.06 : 1,378.81 = 1,378.81 : x
  2. Step 2: Convert to fraction form
    639.06/1,378.81 = 1,378.81/x
  3. Step 3: Cross multiply
    639.06x = 1,378.81 × 1,378.81
  4. Step 4: Simplify right side
    639.06x = 1,901,123.91
  5. Step 5: Solve for x
    x = 1,901,123.91/639.06
  6. Step 6: Final answer
    x = 2,974.86

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Why These Related Problems?

These problems maintain the same ratio (2.16) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.