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Finding the Fourth Proportional to 207.84, 311.90 and 139.49

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Solution

The fourth proportional to 207.84, 311.90 and 139.49 is: 209.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    207.84 : 311.90 = 139.49 : x
  2. Step 2: Convert to fraction form
    207.84/311.90 = 139.49/x
  3. Step 3: Cross multiply
    207.84x = 311.90 × 139.49
  4. Step 4: Simplify right side
    207.84x = 43,506.93
  5. Step 5: Solve for x
    x = 43,506.93/207.84
  6. Step 6: Final answer
    x = 209.33

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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.