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Finding the Fourth Proportional to 139.77, 209.39 and 71.22

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Solution

The fourth proportional to 139.77, 209.39 and 71.22 is: 106.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.77 : 209.39 = 71.22 : x
  2. Step 2: Convert to fraction form
    139.77/209.39 = 71.22/x
  3. Step 3: Cross multiply
    139.77x = 209.39 × 71.22
  4. Step 4: Simplify right side
    139.77x = 14,912.93
  5. Step 5: Solve for x
    x = 14,912.93/139.77
  6. Step 6: Final answer
    x = 106.70

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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.