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Finding the Fourth Proportional to 311.48, 429.60 and 218.20

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Solution

The fourth proportional to 311.48, 429.60 and 218.20 is: 300.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.48 : 429.60 = 218.20 : x
  2. Step 2: Convert to fraction form
    311.48/429.60 = 218.20/x
  3. Step 3: Cross multiply
    311.48x = 429.60 × 218.20
  4. Step 4: Simplify right side
    311.48x = 93,738.72
  5. Step 5: Solve for x
    x = 93,738.72/311.48
  6. Step 6: Final answer
    x = 300.95

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.