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Finding the Fourth Proportional to 311.30, 428.88 and 217.88

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Solution

The fourth proportional to 311.30, 428.88 and 217.88 is: 300.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.30 : 428.88 = 217.88 : x
  2. Step 2: Convert to fraction form
    311.30/428.88 = 217.88/x
  3. Step 3: Cross multiply
    311.30x = 428.88 × 217.88
  4. Step 4: Simplify right side
    311.30x = 93,444.37
  5. Step 5: Solve for x
    x = 93,444.37/311.30
  6. Step 6: Final answer
    x = 300.17

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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.