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Finding the Fourth Proportional to 827.80, 1,239.90 and 665.80

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Solution

The fourth proportional to 827.80, 1,239.90 and 665.80 is: 997.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    827.80 : 1,239.90 = 665.80 : x
  2. Step 2: Convert to fraction form
    827.80/1,239.90 = 665.80/x
  3. Step 3: Cross multiply
    827.80x = 1,239.90 × 665.80
  4. Step 4: Simplify right side
    827.80x = 825,525.42
  5. Step 5: Solve for x
    x = 825,525.42/827.80
  6. Step 6: Final answer
    x = 997.25

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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.