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Finding the Fourth Proportional to 318.78, 479.09 and 211.25

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Solution

The fourth proportional to 318.78, 479.09 and 211.25 is: 317.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    318.78 : 479.09 = 211.25 : x
  2. Step 2: Convert to fraction form
    318.78/479.09 = 211.25/x
  3. Step 3: Cross multiply
    318.78x = 479.09 × 211.25
  4. Step 4: Simplify right side
    318.78x = 101,209.49
  5. Step 5: Solve for x
    x = 101,209.49/318.78
  6. Step 6: Final answer
    x = 317.49

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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.