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Finding the Fourth Proportional to 311.82, 468.20 and 138.68

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Solution

The fourth proportional to 311.82, 468.20 and 138.68 is: 208.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.82 : 468.20 = 138.68 : x
  2. Step 2: Convert to fraction form
    311.82/468.20 = 138.68/x
  3. Step 3: Cross multiply
    311.82x = 468.20 × 138.68
  4. Step 4: Simplify right side
    311.82x = 64,929.98
  5. Step 5: Solve for x
    x = 64,929.98/311.82
  6. Step 6: Final answer
    x = 208.23

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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.