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Finding the Third Proportional to 86.72 and 138.28

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Solution

The third proportional to 86.72 and 138.28 is: 220.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.72 : 138.28 = 138.28 : x
  2. Step 2: Convert to fraction form
    86.72/138.28 = 138.28/x
  3. Step 3: Cross multiply
    86.72x = 138.28 × 138.28
  4. Step 4: Simplify right side
    86.72x = 19,121.70
  5. Step 5: Solve for x
    x = 19,121.70/86.72
  6. Step 6: Final answer
    x = 220.50

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Why These Related Problems?

These problems maintain the same ratio (1.59) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.