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Finding the Fourth Proportional to 809.82, 1,215.13 and 398.47

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Solution

The fourth proportional to 809.82, 1,215.13 and 398.47 is: 597.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    809.82 : 1,215.13 = 398.47 : x
  2. Step 2: Convert to fraction form
    809.82/1,215.13 = 398.47/x
  3. Step 3: Cross multiply
    809.82x = 1,215.13 × 398.47
  4. Step 4: Simplify right side
    809.82x = 484,192.85
  5. Step 5: Solve for x
    x = 484,192.85/809.82
  6. Step 6: Final answer
    x = 597.91

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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.