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Finding the Fourth Proportional to 820.75, 1,231.47 and 512.86

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Solution

The fourth proportional to 820.75, 1,231.47 and 512.86 is: 769.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    820.75 : 1,231.47 = 512.86 : x
  2. Step 2: Convert to fraction form
    820.75/1,231.47 = 512.86/x
  3. Step 3: Cross multiply
    820.75x = 1,231.47 × 512.86
  4. Step 4: Simplify right side
    820.75x = 631,571.70
  5. Step 5: Solve for x
    x = 631,571.70/820.75
  6. Step 6: Final answer
    x = 769.51

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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.