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Finding the Fourth Proportional to 138.75, 191.49 and 80.55

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Solution

The fourth proportional to 138.75, 191.49 and 80.55 is: 111.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.75 : 191.49 = 80.55 : x
  2. Step 2: Convert to fraction form
    138.75/191.49 = 80.55/x
  3. Step 3: Cross multiply
    138.75x = 191.49 × 80.55
  4. Step 4: Simplify right side
    138.75x = 15,424.52
  5. Step 5: Solve for x
    x = 15,424.52/138.75
  6. Step 6: Final answer
    x = 111.17

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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.