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Finding the Fourth Proportional to 821.45, 1,231.79 and 301.31

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Solution

The fourth proportional to 821.45, 1,231.79 and 301.31 is: 451.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.45 : 1,231.79 = 301.31 : x
  2. Step 2: Convert to fraction form
    821.45/1,231.79 = 301.31/x
  3. Step 3: Cross multiply
    821.45x = 1,231.79 × 301.31
  4. Step 4: Simplify right side
    821.45x = 371,152.22
  5. Step 5: Solve for x
    x = 371,152.22/821.45
  6. Step 6: Final answer
    x = 451.82

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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.