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Finding the Fourth Proportional to 312.21, 431.06 and 238.91

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Solution

The fourth proportional to 312.21, 431.06 and 238.91 is: 329.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    312.21 : 431.06 = 238.91 : x
  2. Step 2: Convert to fraction form
    312.21/431.06 = 238.91/x
  3. Step 3: Cross multiply
    312.21x = 431.06 × 238.91
  4. Step 4: Simplify right side
    312.21x = 102,981.19
  5. Step 5: Solve for x
    x = 102,981.19/312.21
  6. Step 6: Final answer
    x = 329.85

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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.