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Finding the Fourth Proportional to 643.21, 887.56 and 422.45

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Solution

The fourth proportional to 643.21, 887.56 and 422.45 is: 582.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.21 : 887.56 = 422.45 : x
  2. Step 2: Convert to fraction form
    643.21/887.56 = 422.45/x
  3. Step 3: Cross multiply
    643.21x = 887.56 × 422.45
  4. Step 4: Simplify right side
    643.21x = 374,947.56
  5. Step 5: Solve for x
    x = 374,947.56/643.21
  6. Step 6: Final answer
    x = 582.93

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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.