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Finding the Fourth Proportional to 399.08, 550.40 and 287.21

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Solution

The fourth proportional to 399.08, 550.40 and 287.21 is: 396.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    399.08 : 550.40 = 287.21 : x
  2. Step 2: Convert to fraction form
    399.08/550.40 = 287.21/x
  3. Step 3: Cross multiply
    399.08x = 550.40 × 287.21
  4. Step 4: Simplify right side
    399.08x = 158,080.38
  5. Step 5: Solve for x
    x = 158,080.38/399.08
  6. Step 6: Final answer
    x = 396.11

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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.