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Finding the Fourth Proportional to 213.78, 320.63 and 76.82

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Solution

The fourth proportional to 213.78, 320.63 and 76.82 is: 115.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    213.78 : 320.63 = 76.82 : x
  2. Step 2: Convert to fraction form
    213.78/320.63 = 76.82/x
  3. Step 3: Cross multiply
    213.78x = 320.63 × 76.82
  4. Step 4: Simplify right side
    213.78x = 24,631.21
  5. Step 5: Solve for x
    x = 24,631.21/213.78
  6. Step 6: Final answer
    x = 115.22

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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.