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Finding the Fourth Proportional to 408.72, 612.81 and 213.66

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Solution

The fourth proportional to 408.72, 612.81 and 213.66 is: 320.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    408.72 : 612.81 = 213.66 : x
  2. Step 2: Convert to fraction form
    408.72/612.81 = 213.66/x
  3. Step 3: Cross multiply
    408.72x = 612.81 × 213.66
  4. Step 4: Simplify right side
    408.72x = 130,932.98
  5. Step 5: Solve for x
    x = 130,932.98/408.72
  6. Step 6: Final answer
    x = 320.35

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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.