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Finding the Fourth Proportional to 643.80, 888.36 and 381.76

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Solution

The fourth proportional to 643.80, 888.36 and 381.76 is: 526.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.80 : 888.36 = 381.76 : x
  2. Step 2: Convert to fraction form
    643.80/888.36 = 381.76/x
  3. Step 3: Cross multiply
    643.80x = 888.36 × 381.76
  4. Step 4: Simplify right side
    643.80x = 339,140.31
  5. Step 5: Solve for x
    x = 339,140.31/643.80
  6. Step 6: Final answer
    x = 526.78

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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.