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Finding the Fourth Proportional to 1,003.20, 1,382.40 and 781.44

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Solution

The fourth proportional to 1,003.20, 1,382.40 and 781.44 is: 1,076.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,003.20 : 1,382.40 = 781.44 : x
  2. Step 2: Convert to fraction form
    1,003.20/1,382.40 = 781.44/x
  3. Step 3: Cross multiply
    1,003.20x = 1,382.40 × 781.44
  4. Step 4: Simplify right side
    1,003.20x = 1,080,262.66
  5. Step 5: Solve for x
    x = 1,080,262.66/1,003.20
  6. Step 6: Final answer
    x = 1,076.82

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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.