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Finding the Fourth Proportional to 213.54, 320.21 and 69.21

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Solution

The fourth proportional to 213.54, 320.21 and 69.21 is: 103.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    213.54 : 320.21 = 69.21 : x
  2. Step 2: Convert to fraction form
    213.54/320.21 = 69.21/x
  3. Step 3: Cross multiply
    213.54x = 320.21 × 69.21
  4. Step 4: Simplify right side
    213.54x = 22,161.39
  5. Step 5: Solve for x
    x = 22,161.39/213.54
  6. Step 6: Final answer
    x = 103.78

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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.