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Finding the Fourth Proportional to 679.97, 938.55 and 400.21

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Solution

The fourth proportional to 679.97, 938.55 and 400.21 is: 552.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    679.97 : 938.55 = 400.21 : x
  2. Step 2: Convert to fraction form
    679.97/938.55 = 400.21/x
  3. Step 3: Cross multiply
    679.97x = 938.55 × 400.21
  4. Step 4: Simplify right side
    679.97x = 375,617.10
  5. Step 5: Solve for x
    x = 375,617.10/679.97
  6. Step 6: Final answer
    x = 552.40

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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.