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Finding the Fourth Proportional to 399.84, 551.78 and 225.20

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Solution

The fourth proportional to 399.84, 551.78 and 225.20 is: 310.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    399.84 : 551.78 = 225.20 : x
  2. Step 2: Convert to fraction form
    399.84/551.78 = 225.20/x
  3. Step 3: Cross multiply
    399.84x = 551.78 × 225.20
  4. Step 4: Simplify right side
    399.84x = 124,260.86
  5. Step 5: Solve for x
    x = 124,260.86/399.84
  6. Step 6: Final answer
    x = 310.78

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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.