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Finding the Fourth Proportional to 821.31, 1,231.65 and 769.68

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Solution

The fourth proportional to 821.31, 1,231.65 and 769.68 is: 1,154.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.31 : 1,231.65 = 769.68 : x
  2. Step 2: Convert to fraction form
    821.31/1,231.65 = 769.68/x
  3. Step 3: Cross multiply
    821.31x = 1,231.65 × 769.68
  4. Step 4: Simplify right side
    821.31x = 947,976.37
  5. Step 5: Solve for x
    x = 947,976.37/821.31
  6. Step 6: Final answer
    x = 1,154.22

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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.