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Finding the Fourth Proportional to 139.05, 191.78 and 83.75

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Solution

The fourth proportional to 139.05, 191.78 and 83.75 is: 115.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.05 : 191.78 = 83.75 : x
  2. Step 2: Convert to fraction form
    139.05/191.78 = 83.75/x
  3. Step 3: Cross multiply
    139.05x = 191.78 × 83.75
  4. Step 4: Simplify right side
    139.05x = 16,062.06
  5. Step 5: Solve for x
    x = 16,062.06/139.05
  6. Step 6: Final answer
    x = 115.51

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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.