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Finding the Third Proportional to 15,720 and 21,360

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Solution

The third proportional to 15,720 and 21,360 is: 29,023.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    15,720 : 21,360 = 21,360 : x
  2. Step 2: Convert to fraction form
    15,720/21,360 = 21,360/x
  3. Step 3: Cross multiply
    15,720x = 21,360 × 21,360
  4. Step 4: Simplify right side
    15,720x = 456,249,600
  5. Step 5: Solve for x
    x = 456,249,600/15,720
  6. Step 6: Final answer
    x = 29,023.51

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Why These Related Problems?

These problems maintain the same ratio (1.36) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.