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Finding the Fourth Proportional to 48.78, 67.31 and 28.05

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Solution

The fourth proportional to 48.78, 67.31 and 28.05 is: 38.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    48.78 : 67.31 = 28.05 : x
  2. Step 2: Convert to fraction form
    48.78/67.31 = 28.05/x
  3. Step 3: Cross multiply
    48.78x = 67.31 × 28.05
  4. Step 4: Simplify right side
    48.78x = 1,887.68
  5. Step 5: Solve for x
    x = 1,887.68/48.78
  6. Step 6: Final answer
    x = 38.70

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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.