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Finding the Fourth Proportional to 643.54, 887.64 and 394.88

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Solution

The fourth proportional to 643.54, 887.64 and 394.88 is: 544.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.54 : 887.64 = 394.88 : x
  2. Step 2: Convert to fraction form
    643.54/887.64 = 394.88/x
  3. Step 3: Cross multiply
    643.54x = 887.64 × 394.88
  4. Step 4: Simplify right side
    643.54x = 350,511.28
  5. Step 5: Solve for x
    x = 350,511.28/643.54
  6. Step 6: Final answer
    x = 544.66

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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.