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Finding the Fourth Proportional to 139.40, 209.11 and 112.51

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Solution

The fourth proportional to 139.40, 209.11 and 112.51 is: 168.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.40 : 209.11 = 112.51 : x
  2. Step 2: Convert to fraction form
    139.40/209.11 = 112.51/x
  3. Step 3: Cross multiply
    139.40x = 209.11 × 112.51
  4. Step 4: Simplify right side
    139.40x = 23,527.43
  5. Step 5: Solve for x
    x = 23,527.43/139.40
  6. Step 6: Final answer
    x = 168.78

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.