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Finding the Fourth Proportional to 311.90, 429.89 and 218.48

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Solution

The fourth proportional to 311.90, 429.89 and 218.48 is: 301.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.90 : 429.89 = 218.48 : x
  2. Step 2: Convert to fraction form
    311.90/429.89 = 218.48/x
  3. Step 3: Cross multiply
    311.90x = 429.89 × 218.48
  4. Step 4: Simplify right side
    311.90x = 93,920.76
  5. Step 5: Solve for x
    x = 93,920.76/311.90
  6. Step 6: Final answer
    x = 301.13

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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.