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Finding the Fourth Proportional to 204.78, 282.57 and 121.90

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Solution

The fourth proportional to 204.78, 282.57 and 121.90 is: 168.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    204.78 : 282.57 = 121.90 : x
  2. Step 2: Convert to fraction form
    204.78/282.57 = 121.90/x
  3. Step 3: Cross multiply
    204.78x = 282.57 × 121.90
  4. Step 4: Simplify right side
    204.78x = 34,445.28
  5. Step 5: Solve for x
    x = 34,445.28/204.78
  6. Step 6: Final answer
    x = 168.21

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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.