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Finding the Fourth Proportional to 813.31, 1,220.31 and 265.65

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Solution

The fourth proportional to 813.31, 1,220.31 and 265.65 is: 398.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    813.31 : 1,220.31 = 265.65 : x
  2. Step 2: Convert to fraction form
    813.31/1,220.31 = 265.65/x
  3. Step 3: Cross multiply
    813.31x = 1,220.31 × 265.65
  4. Step 4: Simplify right side
    813.31x = 324,175.35
  5. Step 5: Solve for x
    x = 324,175.35/813.31
  6. Step 6: Final answer
    x = 398.59

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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.