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Finding the Fourth Proportional to 871.80, 1,305.30 and 679.80

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Solution

The fourth proportional to 871.80, 1,305.30 and 679.80 is: 1,017.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    871.80 : 1,305.30 = 679.80 : x
  2. Step 2: Convert to fraction form
    871.80/1,305.30 = 679.80/x
  3. Step 3: Cross multiply
    871.80x = 1,305.30 × 679.80
  4. Step 4: Simplify right side
    871.80x = 887,342.94
  5. Step 5: Solve for x
    x = 887,342.94/871.80
  6. Step 6: Final answer
    x = 1,017.83

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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.