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Finding the Fourth Proportional to 1,378.50, 2,067.75 and 865.86

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Solution

The fourth proportional to 1,378.50, 2,067.75 and 865.86 is: 1,298.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,378.50 : 2,067.75 = 865.86 : x
  2. Step 2: Convert to fraction form
    1,378.50/2,067.75 = 865.86/x
  3. Step 3: Cross multiply
    1,378.50x = 2,067.75 × 865.86
  4. Step 4: Simplify right side
    1,378.50x = 1,790,382.02
  5. Step 5: Solve for x
    x = 1,790,382.02/1,378.50
  6. Step 6: Final answer
    x = 1,298.79

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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.