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Finding the Fourth Proportional to 680.90, 939.60 and 401.09

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Solution

The fourth proportional to 680.90, 939.60 and 401.09 is: 553.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.90 : 939.60 = 401.09 : x
  2. Step 2: Convert to fraction form
    680.90/939.60 = 401.09/x
  3. Step 3: Cross multiply
    680.90x = 939.60 × 401.09
  4. Step 4: Simplify right side
    680.90x = 376,859.47
  5. Step 5: Solve for x
    x = 376,859.47/680.90
  6. Step 6: Final answer
    x = 553.48

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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.