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Finding the Fourth Proportional to 213.89, 320.72 and 83.88

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Solution

The fourth proportional to 213.89, 320.72 and 83.88 is: 125.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    213.89 : 320.72 = 83.88 : x
  2. Step 2: Convert to fraction form
    213.89/320.72 = 83.88/x
  3. Step 3: Cross multiply
    213.89x = 320.72 × 83.88
  4. Step 4: Simplify right side
    213.89x = 26,901.57
  5. Step 5: Solve for x
    x = 26,901.57/213.89
  6. Step 6: Final answer
    x = 125.78

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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.