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Finding the Fourth Proportional to 318.75, 478.09 and 209.17

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Solution

The fourth proportional to 318.75, 478.09 and 209.17 is: 313.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    318.75 : 478.09 = 209.17 : x
  2. Step 2: Convert to fraction form
    318.75/478.09 = 209.17/x
  3. Step 3: Cross multiply
    318.75x = 478.09 × 209.17
  4. Step 4: Simplify right side
    318.75x = 100,002.09
  5. Step 5: Solve for x
    x = 100,002.09/318.75
  6. Step 6: Final answer
    x = 313.73

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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.