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Finding the Fourth Proportional to 311.09, 428.36 and 281.79

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Solution

The fourth proportional to 311.09, 428.36 and 281.79 is: 388.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.09 : 428.36 = 281.79 : x
  2. Step 2: Convert to fraction form
    311.09/428.36 = 281.79/x
  3. Step 3: Cross multiply
    311.09x = 428.36 × 281.79
  4. Step 4: Simplify right side
    311.09x = 120,706.16
  5. Step 5: Solve for x
    x = 120,706.16/311.09
  6. Step 6: Final answer
    x = 388.02

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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.