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Finding the Fourth Proportional to 318.78, 439.72 and 208.25

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Solution

The fourth proportional to 318.78, 439.72 and 208.25 is: 287.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    318.78 : 439.72 = 208.25 : x
  2. Step 2: Convert to fraction form
    318.78/439.72 = 208.25/x
  3. Step 3: Cross multiply
    318.78x = 439.72 × 208.25
  4. Step 4: Simplify right side
    318.78x = 91,573.68
  5. Step 5: Solve for x
    x = 91,573.68/318.78
  6. Step 6: Final answer
    x = 287.26

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.