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Finding the Fourth Proportional to 311.50, 467.30 and 128.79

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Solution

The fourth proportional to 311.50, 467.30 and 128.79 is: 193.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.50 : 467.30 = 128.79 : x
  2. Step 2: Convert to fraction form
    311.50/467.30 = 128.79/x
  3. Step 3: Cross multiply
    311.50x = 467.30 × 128.79
  4. Step 4: Simplify right side
    311.50x = 60,185.06
  5. Step 5: Solve for x
    x = 60,185.06/311.50
  6. Step 6: Final answer
    x = 193.21

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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.