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Finding the Fourth Proportional to 1,305.81, 1,801.79 and 781.83

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Solution

The fourth proportional to 1,305.81, 1,801.79 and 781.83 is: 1,078.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,305.81 : 1,801.79 = 781.83 : x
  2. Step 2: Convert to fraction form
    1,305.81/1,801.79 = 781.83/x
  3. Step 3: Cross multiply
    1,305.81x = 1,801.79 × 781.83
  4. Step 4: Simplify right side
    1,305.81x = 1,408,689.57
  5. Step 5: Solve for x
    x = 1,408,689.57/1,305.81
  6. Step 6: Final answer
    x = 1,078.79

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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.