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Finding the Fourth Proportional to 679.72, 938.21 and 399.97

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Solution

The fourth proportional to 679.72, 938.21 and 399.97 is: 552.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    679.72 : 938.21 = 399.97 : x
  2. Step 2: Convert to fraction form
    679.72/938.21 = 399.97/x
  3. Step 3: Cross multiply
    679.72x = 938.21 × 399.97
  4. Step 4: Simplify right side
    679.72x = 375,255.85
  5. Step 5: Solve for x
    x = 375,255.85/679.72
  6. Step 6: Final answer
    x = 552.07

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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.