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Finding the Third Proportional to 3.99 and 9.15

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Solution

The third proportional to 3.99 and 9.15 is: 20.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    3.99 : 9.15 = 9.15 : x
  2. Step 2: Convert to fraction form
    3.99/9.15 = 9.15/x
  3. Step 3: Cross multiply
    3.99x = 9.15 × 9.15
  4. Step 4: Simplify right side
    3.99x = 83.71
  5. Step 5: Solve for x
    x = 83.71/3.99
  6. Step 6: Final answer
    x = 20.99

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Why These Related Problems?

These problems maintain the same ratio (2.29) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.