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Finding the Fourth Proportional to 821.76, 1,232.81 and 455.78

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Solution

The fourth proportional to 821.76, 1,232.81 and 455.78 is: 683.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.76 : 1,232.81 = 455.78 : x
  2. Step 2: Convert to fraction form
    821.76/1,232.81 = 455.78/x
  3. Step 3: Cross multiply
    821.76x = 1,232.81 × 455.78
  4. Step 4: Simplify right side
    821.76x = 561,890.14
  5. Step 5: Solve for x
    x = 561,890.14/821.76
  6. Step 6: Final answer
    x = 683.76

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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.