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Finding the Fourth Proportional to 821.08, 1,231.90 and 512.57

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Solution

The fourth proportional to 821.08, 1,231.90 and 512.57 is: 769.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.08 : 1,231.90 = 512.57 : x
  2. Step 2: Convert to fraction form
    821.08/1,231.90 = 512.57/x
  3. Step 3: Cross multiply
    821.08x = 1,231.90 × 512.57
  4. Step 4: Simplify right side
    821.08x = 631,428.82
  5. Step 5: Solve for x
    x = 631,428.82/821.08
  6. Step 6: Final answer
    x = 769.03

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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.