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Finding the Fourth Proportional to 138.91, 191.71 and 83.67

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Solution

The fourth proportional to 138.91, 191.71 and 83.67 is: 115.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.91 : 191.71 = 83.67 : x
  2. Step 2: Convert to fraction form
    138.91/191.71 = 83.67/x
  3. Step 3: Cross multiply
    138.91x = 191.71 × 83.67
  4. Step 4: Simplify right side
    138.91x = 16,039.96
  5. Step 5: Solve for x
    x = 16,039.96/138.91
  6. Step 6: Final answer
    x = 115.47

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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.