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Finding the Fourth Proportional to 1,080.20, 1,491 and 660.80

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Solution

The fourth proportional to 1,080.20, 1,491 and 660.80 is: 912.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,080.20 : 1,491 = 660.80 : x
  2. Step 2: Convert to fraction form
    1,080.20/1,491 = 660.80/x
  3. Step 3: Cross multiply
    1,080.20x = 1,491 × 660.80
  4. Step 4: Simplify right side
    1,080.20x = 985,252.80
  5. Step 5: Solve for x
    x = 985,252.80/1,080.20
  6. Step 6: Final answer
    x = 912.10

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.