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Finding the Fourth Proportional to 231.42, 347.23 and 128.78

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Solution

The fourth proportional to 231.42, 347.23 and 128.78 is: 193.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    231.42 : 347.23 = 128.78 : x
  2. Step 2: Convert to fraction form
    231.42/347.23 = 128.78/x
  3. Step 3: Cross multiply
    231.42x = 347.23 × 128.78
  4. Step 4: Simplify right side
    231.42x = 44,716.28
  5. Step 5: Solve for x
    x = 44,716.28/231.42
  6. Step 6: Final answer
    x = 193.23

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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.