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Finding the Third Proportional to 128.81 and 280.41

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Solution

The third proportional to 128.81 and 280.41 is: 610.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.81 : 280.41 = 280.41 : x
  2. Step 2: Convert to fraction form
    128.81/280.41 = 280.41/x
  3. Step 3: Cross multiply
    128.81x = 280.41 × 280.41
  4. Step 4: Simplify right side
    128.81x = 78,627.67
  5. Step 5: Solve for x
    x = 78,627.67/128.81
  6. Step 6: Final answer
    x = 610.40

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Why These Related Problems?

These problems maintain the same ratio (2.18) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.