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Finding the Fourth Proportional to 643.20, 964.61 and 423.82

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Solution

The fourth proportional to 643.20, 964.61 and 423.82 is: 635.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.20 : 964.61 = 423.82 : x
  2. Step 2: Convert to fraction form
    643.20/964.61 = 423.82/x
  3. Step 3: Cross multiply
    643.20x = 964.61 × 423.82
  4. Step 4: Simplify right side
    643.20x = 408,821.01
  5. Step 5: Solve for x
    x = 408,821.01/643.20
  6. Step 6: Final answer
    x = 635.60

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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.