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Finding the Fourth Proportional to 1,078.96, 1,489.10 and 636.80

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Solution

The fourth proportional to 1,078.96, 1,489.10 and 636.80 is: 878.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,078.96 : 1,489.10 = 636.80 : x
  2. Step 2: Convert to fraction form
    1,078.96/1,489.10 = 636.80/x
  3. Step 3: Cross multiply
    1,078.96x = 1,489.10 × 636.80
  4. Step 4: Simplify right side
    1,078.96x = 948,258.88
  5. Step 5: Solve for x
    x = 948,258.88/1,078.96
  6. Step 6: Final answer
    x = 878.86

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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.