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Finding the Fourth Proportional to 643.88, 888.64 and 395.21

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Solution

The fourth proportional to 643.88, 888.64 and 395.21 is: 545.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.88 : 888.64 = 395.21 : x
  2. Step 2: Convert to fraction form
    643.88/888.64 = 395.21/x
  3. Step 3: Cross multiply
    643.88x = 888.64 × 395.21
  4. Step 4: Simplify right side
    643.88x = 351,200.65
  5. Step 5: Solve for x
    x = 351,200.65/643.88
  6. Step 6: Final answer
    x = 545.44

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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.