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Finding the Third Proportional to 15 and 21.75

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Solution

The third proportional to 15 and 21.75 is: 31.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    15 : 21.75 = 21.75 : x
  2. Step 2: Convert to fraction form
    15/21.75 = 21.75/x
  3. Step 3: Cross multiply
    15x = 21.75 × 21.75
  4. Step 4: Simplify right side
    15x = 473.06
  5. Step 5: Solve for x
    x = 473.06/15
  6. Step 6: Final answer
    x = 31.54

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Why These Related Problems?

These problems maintain the same ratio (1.45) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.