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Finding the Fourth Proportional to 427.20, 640.17 and 253.91

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Solution

The fourth proportional to 427.20, 640.17 and 253.91 is: 380.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    427.20 : 640.17 = 253.91 : x
  2. Step 2: Convert to fraction form
    427.20/640.17 = 253.91/x
  3. Step 3: Cross multiply
    427.20x = 640.17 × 253.91
  4. Step 4: Simplify right side
    427.20x = 162,545.56
  5. Step 5: Solve for x
    x = 162,545.56/427.20
  6. Step 6: Final answer
    x = 380.49

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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.