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Finding the Third Proportional to 642 and 847

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Solution

The third proportional to 642 and 847 is: 1,117.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    642 : 847 = 847 : x
  2. Step 2: Convert to fraction form
    642/847 = 847/x
  3. Step 3: Cross multiply
    642x = 847 × 847
  4. Step 4: Simplify right side
    642x = 717,409
  5. Step 5: Solve for x
    x = 717,409/642
  6. Step 6: Final answer
    x = 1,117.46

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Why These Related Problems?

These problems maintain the same ratio (1.32) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.