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Finding the Fourth Proportional to 821.23, 1,231.47 and 512.62

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Solution

The fourth proportional to 821.23, 1,231.47 and 512.62 is: 768.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.23 : 1,231.47 = 512.62 : x
  2. Step 2: Convert to fraction form
    821.23/1,231.47 = 512.62/x
  3. Step 3: Cross multiply
    821.23x = 1,231.47 × 512.62
  4. Step 4: Simplify right side
    821.23x = 631,276.15
  5. Step 5: Solve for x
    x = 631,276.15/821.23
  6. Step 6: Final answer
    x = 768.70

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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.