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Finding the Third Proportional to 643 and 980

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Solution

The third proportional to 643 and 980 is: 1,493.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    643 : 980 = 980 : x
  2. Step 2: Convert to fraction form
    643/980 = 980/x
  3. Step 3: Cross multiply
    643x = 980 × 980
  4. Step 4: Simplify right side
    643x = 960,400
  5. Step 5: Solve for x
    x = 960,400/643
  6. Step 6: Final answer
    x = 1,493.62

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Why These Related Problems?

These problems maintain the same ratio (1.52) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.