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Finding the Fourth Proportional to 643.56, 965.43 and 399.66

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Solution

The fourth proportional to 643.56, 965.43 and 399.66 is: 599.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.56 : 965.43 = 399.66 : x
  2. Step 2: Convert to fraction form
    643.56/965.43 = 399.66/x
  3. Step 3: Cross multiply
    643.56x = 965.43 × 399.66
  4. Step 4: Simplify right side
    643.56x = 385,843.75
  5. Step 5: Solve for x
    x = 385,843.75/643.56
  6. Step 6: Final answer
    x = 599.55

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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.