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Finding the Third Proportional to 420,928 and 643,920

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Solution

The third proportional to 420,928 and 643,920 is: 985,044.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    420,928 : 643,920 = 643,920 : x
  2. Step 2: Convert to fraction form
    420,928/643,920 = 643,920/x
  3. Step 3: Cross multiply
    420,928x = 643,920 × 643,920
  4. Step 4: Simplify right side
    420,928x = 414,632,966,400
  5. Step 5: Solve for x
    x = 414,632,966,400/420,928
  6. Step 6: Final answer
    x = 985,044.87

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Why These Related Problems?

These problems maintain the same ratio (1.53) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.