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Finding the Fourth Proportional to 213.81, 320.64 and 76.83

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Solution

The fourth proportional to 213.81, 320.64 and 76.83 is: 115.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    213.81 : 320.64 = 76.83 : x
  2. Step 2: Convert to fraction form
    213.81/320.64 = 76.83/x
  3. Step 3: Cross multiply
    213.81x = 320.64 × 76.83
  4. Step 4: Simplify right side
    213.81x = 24,634.77
  5. Step 5: Solve for x
    x = 24,634.77/213.81
  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.