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Finding the Fourth Proportional to 643.76, 963.81 and 438.02

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Solution

The fourth proportional to 643.76, 963.81 and 438.02 is: 655.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.76 : 963.81 = 438.02 : x
  2. Step 2: Convert to fraction form
    643.76/963.81 = 438.02/x
  3. Step 3: Cross multiply
    643.76x = 963.81 × 438.02
  4. Step 4: Simplify right side
    643.76x = 422,161.05
  5. Step 5: Solve for x
    x = 422,161.05/643.76
  6. Step 6: Final answer
    x = 655.78

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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.