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Finding the Fourth Proportional to 825.78, 1,238.88 and 338.70

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Solution

The fourth proportional to 825.78, 1,238.88 and 338.70 is: 508.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    825.78 : 1,238.88 = 338.70 : x
  2. Step 2: Convert to fraction form
    825.78/1,238.88 = 338.70/x
  3. Step 3: Cross multiply
    825.78x = 1,238.88 × 338.70
  4. Step 4: Simplify right side
    825.78x = 419,608.66
  5. Step 5: Solve for x
    x = 419,608.66/825.78
  6. Step 6: Final answer
    x = 508.14

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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.