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Finding the Third Proportional to 211.78 and 318.09

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Solution

The third proportional to 211.78 and 318.09 is: 477.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    211.78 : 318.09 = 318.09 : x
  2. Step 2: Convert to fraction form
    211.78/318.09 = 318.09/x
  3. Step 3: Cross multiply
    211.78x = 318.09 × 318.09
  4. Step 4: Simplify right side
    211.78x = 101,183.63
  5. Step 5: Solve for x
    x = 101,183.63/211.78
  6. Step 6: Final answer
    x = 477.77

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.