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Finding the Fourth Proportional to 398.71, 550.29 and 385.21

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Solution

The fourth proportional to 398.71, 550.29 and 385.21 is: 531.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    398.71 : 550.29 = 385.21 : x
  2. Step 2: Convert to fraction form
    398.71/550.29 = 385.21/x
  3. Step 3: Cross multiply
    398.71x = 550.29 × 385.21
  4. Step 4: Simplify right side
    398.71x = 211,977.21
  5. Step 5: Solve for x
    x = 211,977.21/398.71
  6. Step 6: Final answer
    x = 531.66

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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.