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Finding the Fourth Proportional to 643.78, 964.86 and 424.27

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Solution

The fourth proportional to 643.78, 964.86 and 424.27 is: 635.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.78 : 964.86 = 424.27 : x
  2. Step 2: Convert to fraction form
    643.78/964.86 = 424.27/x
  3. Step 3: Cross multiply
    643.78x = 964.86 × 424.27
  4. Step 4: Simplify right side
    643.78x = 409,361.15
  5. Step 5: Solve for x
    x = 409,361.15/643.78
  6. Step 6: Final answer
    x = 635.87

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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.