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Finding the Third Proportional to 15.12 and 21.80

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Solution

The third proportional to 15.12 and 21.80 is: 31.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    15.12 : 21.80 = 21.80 : x
  2. Step 2: Convert to fraction form
    15.12/21.80 = 21.80/x
  3. Step 3: Cross multiply
    15.12x = 21.80 × 21.80
  4. Step 4: Simplify right side
    15.12x = 475.10
  5. Step 5: Solve for x
    x = 475.10/15.12
  6. Step 6: Final answer
    x = 31.43

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Why These Related Problems?

These problems maintain the same ratio (1.44) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.