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Finding the Fourth Proportional to 211.11, 291.31 and 123.81

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Solution

The fourth proportional to 211.11, 291.31 and 123.81 is: 170.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    211.11 : 291.31 = 123.81 : x
  2. Step 2: Convert to fraction form
    211.11/291.31 = 123.81/x
  3. Step 3: Cross multiply
    211.11x = 291.31 × 123.81
  4. Step 4: Simplify right side
    211.11x = 36,067.09
  5. Step 5: Solve for x
    x = 36,067.09/211.11
  6. Step 6: Final answer
    x = 170.85

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.