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Finding the Fourth Proportional to 211.21, 291.40 and 123.86

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Solution

The fourth proportional to 211.21, 291.40 and 123.86 is: 170.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    211.21 : 291.40 = 123.86 : x
  2. Step 2: Convert to fraction form
    211.21/291.40 = 123.86/x
  3. Step 3: Cross multiply
    211.21x = 291.40 × 123.86
  4. Step 4: Simplify right side
    211.21x = 36,093.22
  5. Step 5: Solve for x
    x = 36,093.22/211.21
  6. Step 6: Final answer
    x = 170.89

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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.