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Finding the Fourth Proportional to 427.28, 640.80 and 211.04

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Solution

The fourth proportional to 427.28, 640.80 and 211.04 is: 316.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    427.28 : 640.80 = 211.04 : x
  2. Step 2: Convert to fraction form
    427.28/640.80 = 211.04/x
  3. Step 3: Cross multiply
    427.28x = 640.80 × 211.04
  4. Step 4: Simplify right side
    427.28x = 135,234.43
  5. Step 5: Solve for x
    x = 135,234.43/427.28
  6. Step 6: Final answer
    x = 316.50

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.