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Finding the Fourth Proportional to 311.57, 429.85 and 212.12

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Solution

The fourth proportional to 311.57, 429.85 and 212.12 is: 292.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.57 : 429.85 = 212.12 : x
  2. Step 2: Convert to fraction form
    311.57/429.85 = 212.12/x
  3. Step 3: Cross multiply
    311.57x = 429.85 × 212.12
  4. Step 4: Simplify right side
    311.57x = 91,179.78
  5. Step 5: Solve for x
    x = 91,179.78/311.57
  6. Step 6: Final answer
    x = 292.65

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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.