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Finding the Fourth Proportional to 428.18, 640.94 and 330.43

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Solution

The fourth proportional to 428.18, 640.94 and 330.43 is: 494.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.18 : 640.94 = 330.43 : x
  2. Step 2: Convert to fraction form
    428.18/640.94 = 330.43/x
  3. Step 3: Cross multiply
    428.18x = 640.94 × 330.43
  4. Step 4: Simplify right side
    428.18x = 211,785.80
  5. Step 5: Solve for x
    x = 211,785.80/428.18
  6. Step 6: Final answer
    x = 494.62

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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.