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Finding the Third Proportional to 128.39 and 171.28

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Solution

The third proportional to 128.39 and 171.28 is: 228.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.39 : 171.28 = 171.28 : x
  2. Step 2: Convert to fraction form
    128.39/171.28 = 171.28/x
  3. Step 3: Cross multiply
    128.39x = 171.28 × 171.28
  4. Step 4: Simplify right side
    128.39x = 29,337.27
  5. Step 5: Solve for x
    x = 29,337.27/128.39
  6. Step 6: Final answer
    x = 228.50

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Why These Related Problems?

These problems maintain the same ratio (1.33) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.