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Finding the Fourth Proportional to 312.70, 431.34 and 238.90

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Solution

The fourth proportional to 312.70, 431.34 and 238.90 is: 329.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    312.70 : 431.34 = 238.90 : x
  2. Step 2: Convert to fraction form
    312.70/431.34 = 238.90/x
  3. Step 3: Cross multiply
    312.70x = 431.34 × 238.90
  4. Step 4: Simplify right side
    312.70x = 103,047.13
  5. Step 5: Solve for x
    x = 103,047.13/312.70
  6. Step 6: Final answer
    x = 329.54

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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.