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Finding the Third Proportional to 4,900 and 7,920

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Solution

The third proportional to 4,900 and 7,920 is: 12,801.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    4,900 : 7,920 = 7,920 : x
  2. Step 2: Convert to fraction form
    4,900/7,920 = 7,920/x
  3. Step 3: Cross multiply
    4,900x = 7,920 × 7,920
  4. Step 4: Simplify right side
    4,900x = 62,726,400
  5. Step 5: Solve for x
    x = 62,726,400/4,900
  6. Step 6: Final answer
    x = 12,801.31

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Why These Related Problems?

These problems maintain the same ratio (1.62) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.