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Finding the Fourth Proportional to 311.12, 428.40 and 223.64

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Solution

The fourth proportional to 311.12, 428.40 and 223.64 is: 307.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.12 : 428.40 = 223.64 : x
  2. Step 2: Convert to fraction form
    311.12/428.40 = 223.64/x
  3. Step 3: Cross multiply
    311.12x = 428.40 × 223.64
  4. Step 4: Simplify right side
    311.12x = 95,807.38
  5. Step 5: Solve for x
    x = 95,807.38/311.12
  6. Step 6: Final answer
    x = 307.94

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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.