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Finding the Fourth Proportional to 989.92, 1,485.60 and 680.96

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Solution

The fourth proportional to 989.92, 1,485.60 and 680.96 is: 1,021.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    989.92 : 1,485.60 = 680.96 : x
  2. Step 2: Convert to fraction form
    989.92/1,485.60 = 680.96/x
  3. Step 3: Cross multiply
    989.92x = 1,485.60 × 680.96
  4. Step 4: Simplify right side
    989.92x = 1,011,634.18
  5. Step 5: Solve for x
    x = 1,011,634.18/989.92
  6. Step 6: Final answer
    x = 1,021.94

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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.