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Finding the Fourth Proportional to 39.82, 54.87 and 30.61

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Solution

The fourth proportional to 39.82, 54.87 and 30.61 is: 42.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    39.82 : 54.87 = 30.61 : x
  2. Step 2: Convert to fraction form
    39.82/54.87 = 30.61/x
  3. Step 3: Cross multiply
    39.82x = 54.87 × 30.61
  4. Step 4: Simplify right side
    39.82x = 1,679.57
  5. Step 5: Solve for x
    x = 1,679.57/39.82
  6. Step 6: Final answer
    x = 42.18

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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.