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Finding the Fourth Proportional to 1,385.57, 2,078.28 and 519.81

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Solution

The fourth proportional to 1,385.57, 2,078.28 and 519.81 is: 779.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,385.57 : 2,078.28 = 519.81 : x
  2. Step 2: Convert to fraction form
    1,385.57/2,078.28 = 519.81/x
  3. Step 3: Cross multiply
    1,385.57x = 2,078.28 × 519.81
  4. Step 4: Simplify right side
    1,385.57x = 1,080,310.73
  5. Step 5: Solve for x
    x = 1,080,310.73/1,385.57
  6. Step 6: Final answer
    x = 779.69

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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.