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Finding the Fourth Proportional to 821.11, 1,231.02 and 431.04

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Solution

The fourth proportional to 821.11, 1,231.02 and 431.04 is: 646.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.11 : 1,231.02 = 431.04 : x
  2. Step 2: Convert to fraction form
    821.11/1,231.02 = 431.04/x
  3. Step 3: Cross multiply
    821.11x = 1,231.02 × 431.04
  4. Step 4: Simplify right side
    821.11x = 530,618.86
  5. Step 5: Solve for x
    x = 530,618.86/821.11
  6. Step 6: Final answer
    x = 646.22

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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.