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Finding the Third Proportional to 128.75 and 305.38

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Solution

The third proportional to 128.75 and 305.38 is: 724.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.75 : 305.38 = 305.38 : x
  2. Step 2: Convert to fraction form
    128.75/305.38 = 305.38/x
  3. Step 3: Cross multiply
    128.75x = 305.38 × 305.38
  4. Step 4: Simplify right side
    128.75x = 93,253.89
  5. Step 5: Solve for x
    x = 93,253.89/128.75
  6. Step 6: Final answer
    x = 724.30

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Why These Related Problems?

These problems maintain the same ratio (2.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.