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Finding the Fourth Proportional to 281.28, 421.72 and 189.72

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Solution

The fourth proportional to 281.28, 421.72 and 189.72 is: 284.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    281.28 : 421.72 = 189.72 : x
  2. Step 2: Convert to fraction form
    281.28/421.72 = 189.72/x
  3. Step 3: Cross multiply
    281.28x = 421.72 × 189.72
  4. Step 4: Simplify right side
    281.28x = 80,008.72
  5. Step 5: Solve for x
    x = 80,008.72/281.28
  6. Step 6: Final answer
    x = 284.45

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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.