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Finding the Fourth Proportional to 427.34, 640.28 and 385.86

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Solution

The fourth proportional to 427.34, 640.28 and 385.86 is: 578.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    427.34 : 640.28 = 385.86 : x
  2. Step 2: Convert to fraction form
    427.34/640.28 = 385.86/x
  3. Step 3: Cross multiply
    427.34x = 640.28 × 385.86
  4. Step 4: Simplify right side
    427.34x = 247,058.44
  5. Step 5: Solve for x
    x = 247,058.44/427.34
  6. Step 6: Final answer
    x = 578.13

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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.