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Finding the Fourth Proportional to 213.68, 320.49 and 91.85

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Solution

The fourth proportional to 213.68, 320.49 and 91.85 is: 137.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    213.68 : 320.49 = 91.85 : x
  2. Step 2: Convert to fraction form
    213.68/320.49 = 91.85/x
  3. Step 3: Cross multiply
    213.68x = 320.49 × 91.85
  4. Step 4: Simplify right side
    213.68x = 29,437.01
  5. Step 5: Solve for x
    x = 29,437.01/213.68
  6. Step 6: Final answer
    x = 137.76

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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.