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Finding the Fourth Proportional to 643.81, 888.56 and 381.91

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Solution

The fourth proportional to 643.81, 888.56 and 381.91 is: 527.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.81 : 888.56 = 381.91 : x
  2. Step 2: Convert to fraction form
    643.81/888.56 = 381.91/x
  3. Step 3: Cross multiply
    643.81x = 888.56 × 381.91
  4. Step 4: Simplify right side
    643.81x = 339,349.95
  5. Step 5: Solve for x
    x = 339,349.95/643.81
  6. Step 6: Final answer
    x = 527.10

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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.