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Finding the Fourth Proportional to 821, 1,231.50 and 243.86

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Solution

The fourth proportional to 821, 1,231.50 and 243.86 is: 365.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    821 : 1,231.50 = 243.86 : x
  2. Step 2: Convert to fraction form
    821/1,231.50 = 243.86/x
  3. Step 3: Cross multiply
    821x = 1,231.50 × 243.86
  4. Step 4: Simplify right side
    821x = 300,313.59
  5. Step 5: Solve for x
    x = 300,313.59/821
  6. Step 6: Final answer
    x = 365.79

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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.