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Finding the Fourth Proportional to 827.46, 1,140.21 and 639.81

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Solution

The fourth proportional to 827.46, 1,140.21 and 639.81 is: 881.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    827.46 : 1,140.21 = 639.81 : x
  2. Step 2: Convert to fraction form
    827.46/1,140.21 = 639.81/x
  3. Step 3: Cross multiply
    827.46x = 1,140.21 × 639.81
  4. Step 4: Simplify right side
    827.46x = 729,517.76
  5. Step 5: Solve for x
    x = 729,517.76/827.46
  6. Step 6: Final answer
    x = 881.64

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.