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Finding the Third Proportional to 128.66 and 266.31

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Solution

The third proportional to 128.66 and 266.31 is: 551.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.66 : 266.31 = 266.31 : x
  2. Step 2: Convert to fraction form
    128.66/266.31 = 266.31/x
  3. Step 3: Cross multiply
    128.66x = 266.31 × 266.31
  4. Step 4: Simplify right side
    128.66x = 70,922.35
  5. Step 5: Solve for x
    x = 70,922.35/128.66
  6. Step 6: Final answer
    x = 551.25

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Why These Related Problems?

These problems maintain the same ratio (2.07) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.