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Finding the Fourth Proportional to 393.78, 543.39 and 225.72

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Solution

The fourth proportional to 393.78, 543.39 and 225.72 is: 311.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    393.78 : 543.39 = 225.72 : x
  2. Step 2: Convert to fraction form
    393.78/543.39 = 225.72/x
  3. Step 3: Cross multiply
    393.78x = 543.39 × 225.72
  4. Step 4: Simplify right side
    393.78x = 122,653.99
  5. Step 5: Solve for x
    x = 122,653.99/393.78
  6. Step 6: Final answer
    x = 311.48

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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.