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Finding the Fourth Proportional to 208.28, 311.84 and 139.64

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Solution

The fourth proportional to 208.28, 311.84 and 139.64 is: 209.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.28 : 311.84 = 139.64 : x
  2. Step 2: Convert to fraction form
    208.28/311.84 = 139.64/x
  3. Step 3: Cross multiply
    208.28x = 311.84 × 139.64
  4. Step 4: Simplify right side
    208.28x = 43,545.34
  5. Step 5: Solve for x
    x = 43,545.34/208.28
  6. Step 6: Final answer
    x = 209.07

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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.