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Finding the Fourth Proportional to 281.28, 421.38 and 172.74

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Solution

The fourth proportional to 281.28, 421.38 and 172.74 is: 258.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    281.28 : 421.38 = 172.74 : x
  2. Step 2: Convert to fraction form
    281.28/421.38 = 172.74/x
  3. Step 3: Cross multiply
    281.28x = 421.38 × 172.74
  4. Step 4: Simplify right side
    281.28x = 72,789.18
  5. Step 5: Solve for x
    x = 72,789.18/281.28
  6. Step 6: Final answer
    x = 258.78

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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.