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Finding the Third Proportional to 8.21 and 12.64

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Solution

The third proportional to 8.21 and 12.64 is: 19.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    8.21 : 12.64 = 12.64 : x
  2. Step 2: Convert to fraction form
    8.21/12.64 = 12.64/x
  3. Step 3: Cross multiply
    8.21x = 12.64 × 12.64
  4. Step 4: Simplify right side
    8.21x = 159.68
  5. Step 5: Solve for x
    x = 159.68/8.21
  6. Step 6: Final answer
    x = 19.45

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Why These Related Problems?

These problems maintain the same ratio (1.54) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.