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Finding the Fourth Proportional to 1,378.64, 2,067.98 and 686.16

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Solution

The fourth proportional to 1,378.64, 2,067.98 and 686.16 is: 1,029.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,378.64 : 2,067.98 = 686.16 : x
  2. Step 2: Convert to fraction form
    1,378.64/2,067.98 = 686.16/x
  3. Step 3: Cross multiply
    1,378.64x = 2,067.98 × 686.16
  4. Step 4: Simplify right side
    1,378.64x = 1,418,961.73
  5. Step 5: Solve for x
    x = 1,418,961.73/1,378.64
  6. Step 6: Final answer
    x = 1,029.25

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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.