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Finding the Fourth Proportional to 822.80, 1,234.20 and 660.80

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Solution

The fourth proportional to 822.80, 1,234.20 and 660.80 is: 991.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    822.80 : 1,234.20 = 660.80 : x
  2. Step 2: Convert to fraction form
    822.80/1,234.20 = 660.80/x
  3. Step 3: Cross multiply
    822.80x = 1,234.20 × 660.80
  4. Step 4: Simplify right side
    822.80x = 815,559.36
  5. Step 5: Solve for x
    x = 815,559.36/822.80
  6. Step 6: Final answer
    x = 991.20

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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.