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Finding the Fourth Proportional to 281.28, 421.20 and 136.80

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Solution

The fourth proportional to 281.28, 421.20 and 136.80 is: 204.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    281.28 : 421.20 = 136.80 : x
  2. Step 2: Convert to fraction form
    281.28/421.20 = 136.80/x
  3. Step 3: Cross multiply
    281.28x = 421.20 × 136.80
  4. Step 4: Simplify right side
    281.28x = 57,620.16
  5. Step 5: Solve for x
    x = 57,620.16/281.28
  6. Step 6: Final answer
    x = 204.85

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.