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Finding the Fourth Proportional to 312.72, 431.64 and 181.78

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Solution

The fourth proportional to 312.72, 431.64 and 181.78 is: 250.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    312.72 : 431.64 = 181.78 : x
  2. Step 2: Convert to fraction form
    312.72/431.64 = 181.78/x
  3. Step 3: Cross multiply
    312.72x = 431.64 × 181.78
  4. Step 4: Simplify right side
    312.72x = 78,463.52
  5. Step 5: Solve for x
    x = 78,463.52/312.72
  6. Step 6: Final answer
    x = 250.91

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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.