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Finding the Fourth Proportional to 139.41, 209.03 and 81.69

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Solution

The fourth proportional to 139.41, 209.03 and 81.69 is: 122.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.41 : 209.03 = 81.69 : x
  2. Step 2: Convert to fraction form
    139.41/209.03 = 81.69/x
  3. Step 3: Cross multiply
    139.41x = 209.03 × 81.69
  4. Step 4: Simplify right side
    139.41x = 17,075.25
  5. Step 5: Solve for x
    x = 17,075.25/139.41
  6. Step 6: Final answer
    x = 122.48

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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.