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Finding the Fourth Proportional to 207.72, 311.53 and 139.65

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Solution

The fourth proportional to 207.72, 311.53 and 139.65 is: 209.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    207.72 : 311.53 = 139.65 : x
  2. Step 2: Convert to fraction form
    207.72/311.53 = 139.65/x
  3. Step 3: Cross multiply
    207.72x = 311.53 × 139.65
  4. Step 4: Simplify right side
    207.72x = 43,504.47
  5. Step 5: Solve for x
    x = 43,504.47/207.72
  6. Step 6: Final answer
    x = 209.44

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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.