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Finding the Third Proportional to 7.80 and 10.86

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Solution

The third proportional to 7.80 and 10.86 is: 15.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    7.80 : 10.86 = 10.86 : x
  2. Step 2: Convert to fraction form
    7.80/10.86 = 10.86/x
  3. Step 3: Cross multiply
    7.80x = 10.86 × 10.86
  4. Step 4: Simplify right side
    7.80x = 118.01
  5. Step 5: Solve for x
    x = 118.01/7.80
  6. Step 6: Final answer
    x = 15.12

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.