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Finding the Fourth Proportional to 311.40, 467.08 and 128.74

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Solution

The fourth proportional to 311.40, 467.08 and 128.74 is: 193.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.40 : 467.08 = 128.74 : x
  2. Step 2: Convert to fraction form
    311.40/467.08 = 128.74/x
  3. Step 3: Cross multiply
    311.40x = 467.08 × 128.74
  4. Step 4: Simplify right side
    311.40x = 60,131.88
  5. Step 5: Solve for x
    x = 60,131.88/311.40
  6. Step 6: Final answer
    x = 193.10

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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.