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Finding the Fourth Proportional to 820.86, 1,231.40 and 265.38

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Solution

The fourth proportional to 820.86, 1,231.40 and 265.38 is: 398.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    820.86 : 1,231.40 = 265.38 : x
  2. Step 2: Convert to fraction form
    820.86/1,231.40 = 265.38/x
  3. Step 3: Cross multiply
    820.86x = 1,231.40 × 265.38
  4. Step 4: Simplify right side
    820.86x = 326,788.93
  5. Step 5: Solve for x
    x = 326,788.93/820.86
  6. Step 6: Final answer
    x = 398.11

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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.