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Finding the Third Proportional to 20 and 30

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Solution

The third proportional to 20 and 30 is: 45

Step by Step Solution

  1. Step 1: Write the proportion equation
    20 : 30 = 30 : x
  2. Step 2: Convert to fraction form
    20/30 = 30/x
  3. Step 3: Cross multiply
    20x = 30 × 30
  4. Step 4: Simplify right side
    20x = 900
  5. Step 5: Solve for x
    x = 900/20
  6. Step 6: Final answer
    x = 45

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Similar ratio
Find third proportional to 30 and 45
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.