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Finding the Fourth Proportional to 821.15, 1,229.51 and 512.38

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Solution

The fourth proportional to 821.15, 1,229.51 and 512.38 is: 767.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.15 : 1,229.51 = 512.38 : x
  2. Step 2: Convert to fraction form
    821.15/1,229.51 = 512.38/x
  3. Step 3: Cross multiply
    821.15x = 1,229.51 × 512.38
  4. Step 4: Simplify right side
    821.15x = 629,973.77
  5. Step 5: Solve for x
    x = 629,973.77/821.15
  6. Step 6: Final answer
    x = 767.19

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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.