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Finding the Fourth Proportional to 312.72, 431.26 and 238.86

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Solution

The fourth proportional to 312.72, 431.26 and 238.86 is: 329.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    312.72 : 431.26 = 238.86 : x
  2. Step 2: Convert to fraction form
    312.72/431.26 = 238.86/x
  3. Step 3: Cross multiply
    312.72x = 431.26 × 238.86
  4. Step 4: Simplify right side
    312.72x = 103,010.76
  5. Step 5: Solve for x
    x = 103,010.76/312.72
  6. Step 6: Final answer
    x = 329.40

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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.