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Finding the Fourth Proportional to 290.78, 400.81 and 220.61

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Solution

The fourth proportional to 290.78, 400.81 and 220.61 is: 304.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    290.78 : 400.81 = 220.61 : x
  2. Step 2: Convert to fraction form
    290.78/400.81 = 220.61/x
  3. Step 3: Cross multiply
    290.78x = 400.81 × 220.61
  4. Step 4: Simplify right side
    290.78x = 88,422.69
  5. Step 5: Solve for x
    x = 88,422.69/290.78
  6. Step 6: Final answer
    x = 304.09

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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.