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Finding the Fourth Proportional to 311.98, 430.57 and 201.78

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Solution

The fourth proportional to 311.98, 430.57 and 201.78 is: 278.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.98 : 430.57 = 201.78 : x
  2. Step 2: Convert to fraction form
    311.98/430.57 = 201.78/x
  3. Step 3: Cross multiply
    311.98x = 430.57 × 201.78
  4. Step 4: Simplify right side
    311.98x = 86,880.41
  5. Step 5: Solve for x
    x = 86,880.41/311.98
  6. Step 6: Final answer
    x = 278.48

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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.