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Finding the Fourth Proportional to 1,989.80, 2,982.24 and 689.75

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Solution

The fourth proportional to 1,989.80, 2,982.24 and 689.75 is: 1,033.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,989.80 : 2,982.24 = 689.75 : x
  2. Step 2: Convert to fraction form
    1,989.80/2,982.24 = 689.75/x
  3. Step 3: Cross multiply
    1,989.80x = 2,982.24 × 689.75
  4. Step 4: Simplify right side
    1,989.80x = 2,057,000.04
  5. Step 5: Solve for x
    x = 2,057,000.04/1,989.80
  6. Step 6: Final answer
    x = 1,033.77

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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.