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Finding the Third Proportional to 138.75 and 213.75

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Solution

The third proportional to 138.75 and 213.75 is: 329.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.75 : 213.75 = 213.75 : x
  2. Step 2: Convert to fraction form
    138.75/213.75 = 213.75/x
  3. Step 3: Cross multiply
    138.75x = 213.75 × 213.75
  4. Step 4: Simplify right side
    138.75x = 45,689.06
  5. Step 5: Solve for x
    x = 45,689.06/138.75
  6. Step 6: Final answer
    x = 329.29

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Why These Related Problems?

These problems maintain the same ratio (1.54) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.