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Finding the Fourth Proportional to 311.12, 429.32 and 212.90

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Solution

The fourth proportional to 311.12, 429.32 and 212.90 is: 293.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.12 : 429.32 = 212.90 : x
  2. Step 2: Convert to fraction form
    311.12/429.32 = 212.90/x
  3. Step 3: Cross multiply
    311.12x = 429.32 × 212.90
  4. Step 4: Simplify right side
    311.12x = 91,402.23
  5. Step 5: Solve for x
    x = 91,402.23/311.12
  6. Step 6: Final answer
    x = 293.78

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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.