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Finding the Fourth Proportional to 81.39, 112.31 and 48.20

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Solution

The fourth proportional to 81.39, 112.31 and 48.20 is: 66.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.39 : 112.31 = 48.20 : x
  2. Step 2: Convert to fraction form
    81.39/112.31 = 48.20/x
  3. Step 3: Cross multiply
    81.39x = 112.31 × 48.20
  4. Step 4: Simplify right side
    81.39x = 5,412.54
  5. Step 5: Solve for x
    x = 5,412.54/81.39
  6. Step 6: Final answer
    x = 66.50

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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.