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Finding the Fourth Proportional to 81.69, 123.18 and 71.67

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Solution

The fourth proportional to 81.69, 123.18 and 71.67 is: 108.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.69 : 123.18 = 71.67 : x
  2. Step 2: Convert to fraction form
    81.69/123.18 = 71.67/x
  3. Step 3: Cross multiply
    81.69x = 123.18 × 71.67
  4. Step 4: Simplify right side
    81.69x = 8,828.31
  5. Step 5: Solve for x
    x = 8,828.31/81.69
  6. Step 6: Final answer
    x = 108.07

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.