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Finding the Fourth Proportional to 2,099.92, 3,149.92 and 639

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Solution

The fourth proportional to 2,099.92, 3,149.92 and 639 is: 958.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    2,099.92 : 3,149.92 = 639 : x
  2. Step 2: Convert to fraction form
    2,099.92/3,149.92 = 639/x
  3. Step 3: Cross multiply
    2,099.92x = 3,149.92 × 639
  4. Step 4: Simplify right side
    2,099.92x = 2,012,798.88
  5. Step 5: Solve for x
    x = 2,012,798.88/2,099.92
  6. Step 6: Final answer
    x = 958.51

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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.