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Finding the Fourth Proportional to 39.91, 55.16 and 30.28

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Solution

The fourth proportional to 39.91, 55.16 and 30.28 is: 41.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    39.91 : 55.16 = 30.28 : x
  2. Step 2: Convert to fraction form
    39.91/55.16 = 30.28/x
  3. Step 3: Cross multiply
    39.91x = 55.16 × 30.28
  4. Step 4: Simplify right side
    39.91x = 1,670.24
  5. Step 5: Solve for x
    x = 1,670.24/39.91
  6. Step 6: Final answer
    x = 41.85

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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.