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Finding the Fourth Proportional to 821.02, 1,231.05 and 561.41

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Solution

The fourth proportional to 821.02, 1,231.05 and 561.41 is: 841.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.02 : 1,231.05 = 561.41 : x
  2. Step 2: Convert to fraction form
    821.02/1,231.05 = 561.41/x
  3. Step 3: Cross multiply
    821.02x = 1,231.05 × 561.41
  4. Step 4: Simplify right side
    821.02x = 691,123.78
  5. Step 5: Solve for x
    x = 691,123.78/821.02
  6. Step 6: Final answer
    x = 841.79

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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.