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Finding the Fourth Proportional to 211.30, 291.60 and 122.79

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Solution

The fourth proportional to 211.30, 291.60 and 122.79 is: 169.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    211.30 : 291.60 = 122.79 : x
  2. Step 2: Convert to fraction form
    211.30/291.60 = 122.79/x
  3. Step 3: Cross multiply
    211.30x = 291.60 × 122.79
  4. Step 4: Simplify right side
    211.30x = 35,805.56
  5. Step 5: Solve for x
    x = 35,805.56/211.30
  6. Step 6: Final answer
    x = 169.45

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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.