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Finding the Third Proportional to 3,990 and 8,115

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Solution

The third proportional to 3,990 and 8,115 is: 16,504.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    3,990 : 8,115 = 8,115 : x
  2. Step 2: Convert to fraction form
    3,990/8,115 = 8,115/x
  3. Step 3: Cross multiply
    3,990x = 8,115 × 8,115
  4. Step 4: Simplify right side
    3,990x = 65,853,225
  5. Step 5: Solve for x
    x = 65,853,225/3,990
  6. Step 6: Final answer
    x = 16,504.57

Related Problems

Find third proportional to 1,995 and 4,057.50
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Double scale
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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (2.03) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.