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Finding the Fourth Proportional to 398.20, 596.78 and 215.72

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Solution

The fourth proportional to 398.20, 596.78 and 215.72 is: 323.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    398.20 : 596.78 = 215.72 : x
  2. Step 2: Convert to fraction form
    398.20/596.78 = 215.72/x
  3. Step 3: Cross multiply
    398.20x = 596.78 × 215.72
  4. Step 4: Simplify right side
    398.20x = 128,737.38
  5. Step 5: Solve for x
    x = 128,737.38/398.20
  6. Step 6: Final answer
    x = 323.30

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.