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Finding the Fourth Proportional to 989.56, 1,481.91 and 815.14

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Solution

The fourth proportional to 989.56, 1,481.91 and 815.14 is: 1,220.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    989.56 : 1,481.91 = 815.14 : x
  2. Step 2: Convert to fraction form
    989.56/1,481.91 = 815.14/x
  3. Step 3: Cross multiply
    989.56x = 1,481.91 × 815.14
  4. Step 4: Simplify right side
    989.56x = 1,207,964.12
  5. Step 5: Solve for x
    x = 1,207,964.12/989.56
  6. Step 6: Final answer
    x = 1,220.71

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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.