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Finding the Fourth Proportional to 643.12, 887.28 and 381.10

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Solution

The fourth proportional to 643.12, 887.28 and 381.10 is: 525.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.12 : 887.28 = 381.10 : x
  2. Step 2: Convert to fraction form
    643.12/887.28 = 381.10/x
  3. Step 3: Cross multiply
    643.12x = 887.28 × 381.10
  4. Step 4: Simplify right side
    643.12x = 338,142.41
  5. Step 5: Solve for x
    x = 338,142.41/643.12
  6. Step 6: Final answer
    x = 525.78

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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.