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Finding the Fourth Proportional to 138.98, 206.90 and 138.17

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Solution

The fourth proportional to 138.98, 206.90 and 138.17 is: 205.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.98 : 206.90 = 138.17 : x
  2. Step 2: Convert to fraction form
    138.98/206.90 = 138.17/x
  3. Step 3: Cross multiply
    138.98x = 206.90 × 138.17
  4. Step 4: Simplify right side
    138.98x = 28,585.65
  5. Step 5: Solve for x
    x = 28,585.65/138.98
  6. Step 6: Final answer
    x = 205.69

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.