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Finding the Fourth Proportional to 1,991.12, 2,982.05 and 1,921.92

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Solution

The fourth proportional to 1,991.12, 2,982.05 and 1,921.92 is: 2,878.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,991.12 : 2,982.05 = 1,921.92 : x
  2. Step 2: Convert to fraction form
    1,991.12/2,982.05 = 1,921.92/x
  3. Step 3: Cross multiply
    1,991.12x = 2,982.05 × 1,921.92
  4. Step 4: Simplify right side
    1,991.12x = 5,731,251.93
  5. Step 5: Solve for x
    x = 5,731,251.93/1,991.12
  6. Step 6: Final answer
    x = 2,878.41

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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.