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Finding the Fourth Proportional to 643.42, 888.45 and 394.91

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Solution

The fourth proportional to 643.42, 888.45 and 394.91 is: 545.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.42 : 888.45 = 394.91 : x
  2. Step 2: Convert to fraction form
    643.42/888.45 = 394.91/x
  3. Step 3: Cross multiply
    643.42x = 888.45 × 394.91
  4. Step 4: Simplify right side
    643.42x = 350,853.35
  5. Step 5: Solve for x
    x = 350,853.35/643.42
  6. Step 6: Final answer
    x = 545.30

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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.