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Finding the Fourth Proportional to 213.85, 320.78 and 76.94

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Solution

The fourth proportional to 213.85, 320.78 and 76.94 is: 115.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    213.85 : 320.78 = 76.94 : x
  2. Step 2: Convert to fraction form
    213.85/320.78 = 76.94/x
  3. Step 3: Cross multiply
    213.85x = 320.78 × 76.94
  4. Step 4: Simplify right side
    213.85x = 24,680.81
  5. Step 5: Solve for x
    x = 24,680.81/213.85
  6. Step 6: Final answer
    x = 115.41

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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.