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Finding the Third Proportional to 642 and 666

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Solution

The third proportional to 642 and 666 is: 690.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    642 : 666 = 666 : x
  2. Step 2: Convert to fraction form
    642/666 = 666/x
  3. Step 3: Cross multiply
    642x = 666 × 666
  4. Step 4: Simplify right side
    642x = 443,556
  5. Step 5: Solve for x
    x = 443,556/642
  6. Step 6: Final answer
    x = 690.90

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Why These Related Problems?

These problems maintain the same ratio (1.04) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.