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Finding the Fourth Proportional to 821.69, 1,229.64 and 513.69

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Solution

The fourth proportional to 821.69, 1,229.64 and 513.69 is: 768.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.69 : 1,229.64 = 513.69 : x
  2. Step 2: Convert to fraction form
    821.69/1,229.64 = 513.69/x
  3. Step 3: Cross multiply
    821.69x = 1,229.64 × 513.69
  4. Step 4: Simplify right side
    821.69x = 631,653.77
  5. Step 5: Solve for x
    x = 631,653.77/821.69
  6. Step 6: Final answer
    x = 768.73

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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.