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Finding the Fourth Proportional to 398.12, 548.51 and 287.42

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Solution

The fourth proportional to 398.12, 548.51 and 287.42 is: 395.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    398.12 : 548.51 = 287.42 : x
  2. Step 2: Convert to fraction form
    398.12/548.51 = 287.42/x
  3. Step 3: Cross multiply
    398.12x = 548.51 × 287.42
  4. Step 4: Simplify right side
    398.12x = 157,648.56
  5. Step 5: Solve for x
    x = 157,648.56/398.12
  6. Step 6: Final answer
    x = 395.99

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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.