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Finding the Fourth Proportional to 287.78, 396.78 and 225.42

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Solution

The fourth proportional to 287.78, 396.78 and 225.42 is: 310.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    287.78 : 396.78 = 225.42 : x
  2. Step 2: Convert to fraction form
    287.78/396.78 = 225.42/x
  3. Step 3: Cross multiply
    287.78x = 396.78 × 225.42
  4. Step 4: Simplify right side
    287.78x = 89,442.15
  5. Step 5: Solve for x
    x = 89,442.15/287.78
  6. Step 6: Final answer
    x = 310.80

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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.