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Finding the Fourth Proportional to 643.41, 888.10 and 391.43

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Solution

The fourth proportional to 643.41, 888.10 and 391.43 is: 540.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.41 : 888.10 = 391.43 : x
  2. Step 2: Convert to fraction form
    643.41/888.10 = 391.43/x
  3. Step 3: Cross multiply
    643.41x = 888.10 × 391.43
  4. Step 4: Simplify right side
    643.41x = 347,630.22
  5. Step 5: Solve for x
    x = 347,630.22/643.41
  6. Step 6: Final answer
    x = 540.29

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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.