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Finding the Fourth Proportional to 399.24, 550.32 and 305.78

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Solution

The fourth proportional to 399.24, 550.32 and 305.78 is: 421.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    399.24 : 550.32 = 305.78 : x
  2. Step 2: Convert to fraction form
    399.24/550.32 = 305.78/x
  3. Step 3: Cross multiply
    399.24x = 550.32 × 305.78
  4. Step 4: Simplify right side
    399.24x = 168,276.85
  5. Step 5: Solve for x
    x = 168,276.85/399.24
  6. Step 6: Final answer
    x = 421.49

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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.