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Finding the Fourth Proportional to 871.21, 1,306.85 and 286.21

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Solution

The fourth proportional to 871.21, 1,306.85 and 286.21 is: 429.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    871.21 : 1,306.85 = 286.21 : x
  2. Step 2: Convert to fraction form
    871.21/1,306.85 = 286.21/x
  3. Step 3: Cross multiply
    871.21x = 1,306.85 × 286.21
  4. Step 4: Simplify right side
    871.21x = 374,033.54
  5. Step 5: Solve for x
    x = 374,033.54/871.21
  6. Step 6: Final answer
    x = 429.33

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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.