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Finding the Third Proportional to 638 and 724

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Solution

The third proportional to 638 and 724 is: 821.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    638 : 724 = 724 : x
  2. Step 2: Convert to fraction form
    638/724 = 724/x
  3. Step 3: Cross multiply
    638x = 724 × 724
  4. Step 4: Simplify right side
    638x = 524,176
  5. Step 5: Solve for x
    x = 524,176/638
  6. Step 6: Final answer
    x = 821.59

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Why These Related Problems?

These problems maintain the same ratio (1.13) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.