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Finding the Fourth Proportional to 399.20, 550.68 and 274.64

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Solution

The fourth proportional to 399.20, 550.68 and 274.64 is: 378.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    399.20 : 550.68 = 274.64 : x
  2. Step 2: Convert to fraction form
    399.20/550.68 = 274.64/x
  3. Step 3: Cross multiply
    399.20x = 550.68 × 274.64
  4. Step 4: Simplify right side
    399.20x = 151,238.76
  5. Step 5: Solve for x
    x = 151,238.76/399.20
  6. Step 6: Final answer
    x = 378.85

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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.