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Finding the Fourth Proportional to 139.43, 207.63 and 138.65

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Solution

The fourth proportional to 139.43, 207.63 and 138.65 is: 206.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.43 : 207.63 = 138.65 : x
  2. Step 2: Convert to fraction form
    139.43/207.63 = 138.65/x
  3. Step 3: Cross multiply
    139.43x = 207.63 × 138.65
  4. Step 4: Simplify right side
    139.43x = 28,786.86
  5. Step 5: Solve for x
    x = 28,786.86/139.43
  6. Step 6: Final answer
    x = 206.47

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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.