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Finding the Fourth Proportional to 643.28, 887.20 and 422.45

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Solution

The fourth proportional to 643.28, 887.20 and 422.45 is: 582.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.28 : 887.20 = 422.45 : x
  2. Step 2: Convert to fraction form
    643.28/887.20 = 422.45/x
  3. Step 3: Cross multiply
    643.28x = 887.20 × 422.45
  4. Step 4: Simplify right side
    643.28x = 374,797.85
  5. Step 5: Solve for x
    x = 374,797.85/643.28
  6. Step 6: Final answer
    x = 582.64

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.