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Finding the Fourth Proportional to 26.78, 40.21 and 20.79

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Solution

The fourth proportional to 26.78, 40.21 and 20.79 is: 31.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    26.78 : 40.21 = 20.79 : x
  2. Step 2: Convert to fraction form
    26.78/40.21 = 20.79/x
  3. Step 3: Cross multiply
    26.78x = 40.21 × 20.79
  4. Step 4: Simplify right side
    26.78x = 835.91
  5. Step 5: Solve for x
    x = 835.91/26.78
  6. Step 6: Final answer
    x = 31.22

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.