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Finding the Fourth Proportional to 399.36, 550.80 and 321.60

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Solution

The fourth proportional to 399.36, 550.80 and 321.60 is: 443.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    399.36 : 550.80 = 321.60 : x
  2. Step 2: Convert to fraction form
    399.36/550.80 = 321.60/x
  3. Step 3: Cross multiply
    399.36x = 550.80 × 321.60
  4. Step 4: Simplify right side
    399.36x = 177,137.28
  5. Step 5: Solve for x
    x = 177,137.28/399.36
  6. Step 6: Final answer
    x = 443.55

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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.