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Finding the Fourth Proportional to 26.50, 39.91 and 19.78

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Solution

The fourth proportional to 26.50, 39.91 and 19.78 is: 29.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    26.50 : 39.91 = 19.78 : x
  2. Step 2: Convert to fraction form
    26.50/39.91 = 19.78/x
  3. Step 3: Cross multiply
    26.50x = 39.91 × 19.78
  4. Step 4: Simplify right side
    26.50x = 789.42
  5. Step 5: Solve for x
    x = 789.42/26.50
  6. Step 6: Final answer
    x = 29.79

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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.