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Finding the Fourth Proportional to 207.85, 311.78 and 139.51

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Solution

The fourth proportional to 207.85, 311.78 and 139.51 is: 209.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    207.85 : 311.78 = 139.51 : x
  2. Step 2: Convert to fraction form
    207.85/311.78 = 139.51/x
  3. Step 3: Cross multiply
    207.85x = 311.78 × 139.51
  4. Step 4: Simplify right side
    207.85x = 43,496.43
  5. Step 5: Solve for x
    x = 43,496.43/207.85
  6. Step 6: Final answer
    x = 209.27

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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.