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Finding the Third Proportional to 128.74 and 203.45

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Solution

The third proportional to 128.74 and 203.45 is: 321.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.74 : 203.45 = 203.45 : x
  2. Step 2: Convert to fraction form
    128.74/203.45 = 203.45/x
  3. Step 3: Cross multiply
    128.74x = 203.45 × 203.45
  4. Step 4: Simplify right side
    128.74x = 41,391.58
  5. Step 5: Solve for x
    x = 41,391.58/128.74
  6. Step 6: Final answer
    x = 321.51

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Why These Related Problems?

These problems maintain the same ratio (1.58) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.