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Finding the Fourth Proportional to 989.79, 1,481.13 and 729.18

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Solution

The fourth proportional to 989.79, 1,481.13 and 729.18 is: 1,091.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    989.79 : 1,481.13 = 729.18 : x
  2. Step 2: Convert to fraction form
    989.79/1,481.13 = 729.18/x
  3. Step 3: Cross multiply
    989.79x = 1,481.13 × 729.18
  4. Step 4: Simplify right side
    989.79x = 1,080,010.37
  5. Step 5: Solve for x
    x = 1,080,010.37/989.79
  6. Step 6: Final answer
    x = 1,091.15

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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.