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Finding the Third Proportional to 21,288 and 39,120

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Solution

The third proportional to 21,288 and 39,120 is: 71,889.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    21,288 : 39,120 = 39,120 : x
  2. Step 2: Convert to fraction form
    21,288/39,120 = 39,120/x
  3. Step 3: Cross multiply
    21,288x = 39,120 × 39,120
  4. Step 4: Simplify right side
    21,288x = 1,530,374,400
  5. Step 5: Solve for x
    x = 1,530,374,400/21,288
  6. Step 6: Final answer
    x = 71,889.06

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Why These Related Problems?

These problems maintain the same ratio (1.84) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.