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Finding the Fourth Proportional to 643.87, 965.24 and 399.86

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Solution

The fourth proportional to 643.87, 965.24 and 399.86 is: 599.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.87 : 965.24 = 399.86 : x
  2. Step 2: Convert to fraction form
    643.87/965.24 = 399.86/x
  3. Step 3: Cross multiply
    643.87x = 965.24 × 399.86
  4. Step 4: Simplify right side
    643.87x = 385,954.04
  5. Step 5: Solve for x
    x = 385,954.04/643.87
  6. Step 6: Final answer
    x = 599.43

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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.