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Finding the Fourth Proportional to 138.47, 191.07 and 83.21

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Solution

The fourth proportional to 138.47, 191.07 and 83.21 is: 114.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.47 : 191.07 = 83.21 : x
  2. Step 2: Convert to fraction form
    138.47/191.07 = 83.21/x
  3. Step 3: Cross multiply
    138.47x = 191.07 × 83.21
  4. Step 4: Simplify right side
    138.47x = 15,897.98
  5. Step 5: Solve for x
    x = 15,897.98/138.47
  6. Step 6: Final answer
    x = 114.82

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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.