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Finding the Fourth Proportional to 643.72, 888.42 and 395

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Solution

The fourth proportional to 643.72, 888.42 and 395 is: 545.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.72 : 888.42 = 395 : x
  2. Step 2: Convert to fraction form
    643.72/888.42 = 395/x
  3. Step 3: Cross multiply
    643.72x = 888.42 × 395
  4. Step 4: Simplify right side
    643.72x = 350,925.90
  5. Step 5: Solve for x
    x = 350,925.90/643.72
  6. Step 6: Final answer
    x = 545.15

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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.