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Finding the Fourth Proportional to 312.78, 431.16 and 225.54

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Solution

The fourth proportional to 312.78, 431.16 and 225.54 is: 310.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    312.78 : 431.16 = 225.54 : x
  2. Step 2: Convert to fraction form
    312.78/431.16 = 225.54/x
  3. Step 3: Cross multiply
    312.78x = 431.16 × 225.54
  4. Step 4: Simplify right side
    312.78x = 97,243.83
  5. Step 5: Solve for x
    x = 97,243.83/312.78
  6. Step 6: Final answer
    x = 310.90

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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.