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Finding the Third Proportional to 7.78 and 11.72

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Solution

The third proportional to 7.78 and 11.72 is: 17.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    7.78 : 11.72 = 11.72 : x
  2. Step 2: Convert to fraction form
    7.78/11.72 = 11.72/x
  3. Step 3: Cross multiply
    7.78x = 11.72 × 11.72
  4. Step 4: Simplify right side
    7.78x = 137.33
  5. Step 5: Solve for x
    x = 137.33/7.78
  6. Step 6: Final answer
    x = 17.65

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.