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Finding the Fourth Proportional to 81.69, 122.40 and 47.48

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Solution

The fourth proportional to 81.69, 122.40 and 47.48 is: 71.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.69 : 122.40 = 47.48 : x
  2. Step 2: Convert to fraction form
    81.69/122.40 = 47.48/x
  3. Step 3: Cross multiply
    81.69x = 122.40 × 47.48
  4. Step 4: Simplify right side
    81.69x = 5,810.94
  5. Step 5: Solve for x
    x = 5,810.94/81.69
  6. Step 6: Final answer
    x = 71.13

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.