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Finding the Third Proportional to 7.78 and 19.31

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Solution

The third proportional to 7.78 and 19.31 is: 47.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    7.78 : 19.31 = 19.31 : x
  2. Step 2: Convert to fraction form
    7.78/19.31 = 19.31/x
  3. Step 3: Cross multiply
    7.78x = 19.31 × 19.31
  4. Step 4: Simplify right side
    7.78x = 372.97
  5. Step 5: Solve for x
    x = 372.97/7.78
  6. Step 6: Final answer
    x = 47.93

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Why These Related Problems?

These problems maintain the same ratio (2.48) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.