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Finding the Fourth Proportional to 1,079.28, 1,488.90 and 636.90

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Solution

The fourth proportional to 1,079.28, 1,488.90 and 636.90 is: 878.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,079.28 : 1,488.90 = 636.90 : x
  2. Step 2: Convert to fraction form
    1,079.28/1,488.90 = 636.90/x
  3. Step 3: Cross multiply
    1,079.28x = 1,488.90 × 636.90
  4. Step 4: Simplify right side
    1,079.28x = 948,280.41
  5. Step 5: Solve for x
    x = 948,280.41/1,079.28
  6. Step 6: Final answer
    x = 878.62

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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.