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Finding the Third Proportional to 211.31 and 286.78

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Solution

The third proportional to 211.31 and 286.78 is: 389.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    211.31 : 286.78 = 286.78 : x
  2. Step 2: Convert to fraction form
    211.31/286.78 = 286.78/x
  3. Step 3: Cross multiply
    211.31x = 286.78 × 286.78
  4. Step 4: Simplify right side
    211.31x = 82,243.49
  5. Step 5: Solve for x
    x = 82,243.49/211.31
  6. Step 6: Final answer
    x = 389.20

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Why These Related Problems?

These problems maintain the same ratio (1.36) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.