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Finding the Fourth Proportional to 311.99, 468.20 and 138.85

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Solution

The fourth proportional to 311.99, 468.20 and 138.85 is: 208.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.99 : 468.20 = 138.85 : x
  2. Step 2: Convert to fraction form
    311.99/468.20 = 138.85/x
  3. Step 3: Cross multiply
    311.99x = 468.20 × 138.85
  4. Step 4: Simplify right side
    311.99x = 65,009.57
  5. Step 5: Solve for x
    x = 65,009.57/311.99
  6. Step 6: Final answer
    x = 208.37

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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.