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Finding the Fourth Proportional to 312.78, 431.49 and 194.72

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Solution

The fourth proportional to 312.78, 431.49 and 194.72 is: 268.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    312.78 : 431.49 = 194.72 : x
  2. Step 2: Convert to fraction form
    312.78/431.49 = 194.72/x
  3. Step 3: Cross multiply
    312.78x = 431.49 × 194.72
  4. Step 4: Simplify right side
    312.78x = 84,019.73
  5. Step 5: Solve for x
    x = 84,019.73/312.78
  6. Step 6: Final answer
    x = 268.62

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.