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Finding the Third Proportional to 128.78 and 277.49

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Solution

The third proportional to 128.78 and 277.49 is: 597.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.78 : 277.49 = 277.49 : x
  2. Step 2: Convert to fraction form
    128.78/277.49 = 277.49/x
  3. Step 3: Cross multiply
    128.78x = 277.49 × 277.49
  4. Step 4: Simplify right side
    128.78x = 76,999.75
  5. Step 5: Solve for x
    x = 76,999.75/128.78
  6. Step 6: Final answer
    x = 597.93

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Why These Related Problems?

These problems maintain the same ratio (2.15) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.