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Finding the Fourth Proportional to 231.72, 347.70 and 128.88

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Solution

The fourth proportional to 231.72, 347.70 and 128.88 is: 193.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    231.72 : 347.70 = 128.88 : x
  2. Step 2: Convert to fraction form
    231.72/347.70 = 128.88/x
  3. Step 3: Cross multiply
    231.72x = 347.70 × 128.88
  4. Step 4: Simplify right side
    231.72x = 44,811.58
  5. Step 5: Solve for x
    x = 44,811.58/231.72
  6. Step 6: Final answer
    x = 193.39

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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.