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Finding the Fourth Proportional to 213.69, 320.61 and 76.75

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Solution

The fourth proportional to 213.69, 320.61 and 76.75 is: 115.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    213.69 : 320.61 = 76.75 : x
  2. Step 2: Convert to fraction form
    213.69/320.61 = 76.75/x
  3. Step 3: Cross multiply
    213.69x = 320.61 × 76.75
  4. Step 4: Simplify right side
    213.69x = 24,605.87
  5. Step 5: Solve for x
    x = 24,605.87/213.69
  6. Step 6: Final answer
    x = 115.15

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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.