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Finding the Fourth Proportional to 290.17, 400.21 and 211.78

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Solution

The fourth proportional to 290.17, 400.21 and 211.78 is: 292.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    290.17 : 400.21 = 211.78 : x
  2. Step 2: Convert to fraction form
    290.17/400.21 = 211.78/x
  3. Step 3: Cross multiply
    290.17x = 400.21 × 211.78
  4. Step 4: Simplify right side
    290.17x = 84,756.47
  5. Step 5: Solve for x
    x = 84,756.47/290.17
  6. Step 6: Final answer
    x = 292.09

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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.