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Finding the Fourth Proportional to 231.12, 318.95 and 128.79

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Solution

The fourth proportional to 231.12, 318.95 and 128.79 is: 177.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    231.12 : 318.95 = 128.79 : x
  2. Step 2: Convert to fraction form
    231.12/318.95 = 128.79/x
  3. Step 3: Cross multiply
    231.12x = 318.95 × 128.79
  4. Step 4: Simplify right side
    231.12x = 41,076.93
  5. Step 5: Solve for x
    x = 41,076.93/231.12
  6. Step 6: Final answer
    x = 177.73

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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.