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Finding the Fourth Proportional to 311.51, 467.28 and 128.87

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Solution

The fourth proportional to 311.51, 467.28 and 128.87 is: 193.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.51 : 467.28 = 128.87 : x
  2. Step 2: Convert to fraction form
    311.51/467.28 = 128.87/x
  3. Step 3: Cross multiply
    311.51x = 467.28 × 128.87
  4. Step 4: Simplify right side
    311.51x = 60,220.42
  5. Step 5: Solve for x
    x = 60,220.42/311.51
  6. Step 6: Final answer
    x = 193.32

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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.