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Finding the Third Proportional to 5 and 7

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Solution

The third proportional to 5 and 7 is: 9.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    5 : 7 = 7 : x
  2. Step 2: Convert to fraction form
    5/7 = 7/x
  3. Step 3: Cross multiply
    5x = 7 × 7
  4. Step 4: Simplify right side
    5x = 49
  5. Step 5: Solve for x
    x = 49/5
  6. Step 6: Final answer
    x = 9.80

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Why These Related Problems?

These problems maintain the same ratio (1.40) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.