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Finding the Fourth Proportional to 39.19, 54.09 and 21.71

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Solution

The fourth proportional to 39.19, 54.09 and 21.71 is: 29.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    39.19 : 54.09 = 21.71 : x
  2. Step 2: Convert to fraction form
    39.19/54.09 = 21.71/x
  3. Step 3: Cross multiply
    39.19x = 54.09 × 21.71
  4. Step 4: Simplify right side
    39.19x = 1,174.06
  5. Step 5: Solve for x
    x = 1,174.06/39.19
  6. Step 6: Final answer
    x = 29.96

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.