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Finding the Fourth Proportional to 213.91, 320.85 and 142.21

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Solution

The fourth proportional to 213.91, 320.85 and 142.21 is: 213.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    213.91 : 320.85 = 142.21 : x
  2. Step 2: Convert to fraction form
    213.91/320.85 = 142.21/x
  3. Step 3: Cross multiply
    213.91x = 320.85 × 142.21
  4. Step 4: Simplify right side
    213.91x = 45,628.08
  5. Step 5: Solve for x
    x = 45,628.08/213.91
  6. Step 6: Final answer
    x = 213.31

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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.