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Finding the Fourth Proportional to 427.10, 638.30 and 311.78

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Solution

The fourth proportional to 427.10, 638.30 and 311.78 is: 465.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    427.10 : 638.30 = 311.78 : x
  2. Step 2: Convert to fraction form
    427.10/638.30 = 311.78/x
  3. Step 3: Cross multiply
    427.10x = 638.30 × 311.78
  4. Step 4: Simplify right side
    427.10x = 199,011.55
  5. Step 5: Solve for x
    x = 199,011.55/427.10
  6. Step 6: Final answer
    x = 465.97

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.