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Finding the Fourth Proportional to 311.08, 428.42 and 286.76

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Solution

The fourth proportional to 311.08, 428.42 and 286.76 is: 394.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.08 : 428.42 = 286.76 : x
  2. Step 2: Convert to fraction form
    311.08/428.42 = 286.76/x
  3. Step 3: Cross multiply
    311.08x = 428.42 × 286.76
  4. Step 4: Simplify right side
    311.08x = 122,853.72
  5. Step 5: Solve for x
    x = 122,853.72/311.08
  6. Step 6: Final answer
    x = 394.93

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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.