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Finding the Fourth Proportional to 213.93, 321.03 and 85.68

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Solution

The fourth proportional to 213.93, 321.03 and 85.68 is: 128.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    213.93 : 321.03 = 85.68 : x
  2. Step 2: Convert to fraction form
    213.93/321.03 = 85.68/x
  3. Step 3: Cross multiply
    213.93x = 321.03 × 85.68
  4. Step 4: Simplify right side
    213.93x = 27,505.85
  5. Step 5: Solve for x
    x = 27,505.85/213.93
  6. Step 6: Final answer
    x = 128.57

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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.