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Finding the Fourth Proportional to 39.78, 55.13 and 39.06

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Solution

The fourth proportional to 39.78, 55.13 and 39.06 is: 54.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    39.78 : 55.13 = 39.06 : x
  2. Step 2: Convert to fraction form
    39.78/55.13 = 39.06/x
  3. Step 3: Cross multiply
    39.78x = 55.13 × 39.06
  4. Step 4: Simplify right side
    39.78x = 2,153.18
  5. Step 5: Solve for x
    x = 2,153.18/39.78
  6. Step 6: Final answer
    x = 54.13

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.