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Finding the Fourth Proportional to 138.99, 209.25 and 121.98

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Solution

The fourth proportional to 138.99, 209.25 and 121.98 is: 183.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.99 : 209.25 = 121.98 : x
  2. Step 2: Convert to fraction form
    138.99/209.25 = 121.98/x
  3. Step 3: Cross multiply
    138.99x = 209.25 × 121.98
  4. Step 4: Simplify right side
    138.99x = 25,522.66
  5. Step 5: Solve for x
    x = 25,522.66/138.99
  6. Step 6: Final answer
    x = 183.64

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.