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Finding the Third Proportional to 31.85 and 69.40

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Solution

The third proportional to 31.85 and 69.40 is: 151.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.85 : 69.40 = 69.40 : x
  2. Step 2: Convert to fraction form
    31.85/69.40 = 69.40/x
  3. Step 3: Cross multiply
    31.85x = 69.40 × 69.40
  4. Step 4: Simplify right side
    31.85x = 4,816.14
  5. Step 5: Solve for x
    x = 4,816.14/31.85
  6. Step 6: Final answer
    x = 151.21

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Why These Related Problems?

These problems maintain the same ratio (2.18) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.