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Finding the Fourth Proportional to 863.18, 1,286.20 and 821.34

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Solution

The fourth proportional to 863.18, 1,286.20 and 821.34 is: 1,223.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    863.18 : 1,286.20 = 821.34 : x
  2. Step 2: Convert to fraction form
    863.18/1,286.20 = 821.34/x
  3. Step 3: Cross multiply
    863.18x = 1,286.20 × 821.34
  4. Step 4: Simplify right side
    863.18x = 1,056,405.45
  5. Step 5: Solve for x
    x = 1,056,405.45/863.18
  6. Step 6: Final answer
    x = 1,223.85

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.