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Finding the Fourth Proportional to 3,939, 5,910.78 and 1,991.40

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Solution

The fourth proportional to 3,939, 5,910.78 and 1,991.40 is: 2,988.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    3,939 : 5,910.78 = 1,991.40 : x
  2. Step 2: Convert to fraction form
    3,939/5,910.78 = 1,991.40/x
  3. Step 3: Cross multiply
    3,939x = 5,910.78 × 1,991.40
  4. Step 4: Simplify right side
    3,939x = 11,770,727.29
  5. Step 5: Solve for x
    x = 11,770,727.29/3,939
  6. Step 6: Final answer
    x = 2,988.25

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1.5x scale

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.