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Finding the Fourth Proportional to 39.80, 54.80 and 38.68

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Solution

The fourth proportional to 39.80, 54.80 and 38.68 is: 53.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    39.80 : 54.80 = 38.68 : x
  2. Step 2: Convert to fraction form
    39.80/54.80 = 38.68/x
  3. Step 3: Cross multiply
    39.80x = 54.80 × 38.68
  4. Step 4: Simplify right side
    39.80x = 2,119.66
  5. Step 5: Solve for x
    x = 2,119.66/39.80
  6. Step 6: Final answer
    x = 53.26

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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.