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Finding the Third Proportional to 30.80 and 69.61

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Solution

The third proportional to 30.80 and 69.61 is: 157.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    30.80 : 69.61 = 69.61 : x
  2. Step 2: Convert to fraction form
    30.80/69.61 = 69.61/x
  3. Step 3: Cross multiply
    30.80x = 69.61 × 69.61
  4. Step 4: Simplify right side
    30.80x = 4,845.47
  5. Step 5: Solve for x
    x = 4,845.47/30.80
  6. Step 6: Final answer
    x = 157.34

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Why These Related Problems?

These problems maintain the same ratio (2.26) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.