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Finding the Fourth Proportional to 312.80, 431.60 and 181.78

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Solution

The fourth proportional to 312.80, 431.60 and 181.78 is: 250.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    312.80 : 431.60 = 181.78 : x
  2. Step 2: Convert to fraction form
    312.80/431.60 = 181.78/x
  3. Step 3: Cross multiply
    312.80x = 431.60 × 181.78
  4. Step 4: Simplify right side
    312.80x = 78,456.25
  5. Step 5: Solve for x
    x = 78,456.25/312.80
  6. Step 6: Final answer
    x = 250.82

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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.