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Finding the Third Proportional to 87 and 139

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Solution

The third proportional to 87 and 139 is: 222.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    87 : 139 = 139 : x
  2. Step 2: Convert to fraction form
    87/139 = 139/x
  3. Step 3: Cross multiply
    87x = 139 × 139
  4. Step 4: Simplify right side
    87x = 19,321
  5. Step 5: Solve for x
    x = 19,321/87
  6. Step 6: Final answer
    x = 222.08

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Why These Related Problems?

These problems maintain the same ratio (1.60) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.