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Finding the Third Proportional to 15 and 20.75

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Solution

The third proportional to 15 and 20.75 is: 28.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    15 : 20.75 = 20.75 : x
  2. Step 2: Convert to fraction form
    15/20.75 = 20.75/x
  3. Step 3: Cross multiply
    15x = 20.75 × 20.75
  4. Step 4: Simplify right side
    15x = 430.56
  5. Step 5: Solve for x
    x = 430.56/15
  6. Step 6: Final answer
    x = 28.70

Related Problems

Find third proportional to 7.50 and 10.38
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Double scale
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Similar ratio
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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.