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Finding the Fourth Proportional to 2,099.85, 3,149.78 and 639

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Solution

The fourth proportional to 2,099.85, 3,149.78 and 639 is: 958.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    2,099.85 : 3,149.78 = 639 : x
  2. Step 2: Convert to fraction form
    2,099.85/3,149.78 = 639/x
  3. Step 3: Cross multiply
    2,099.85x = 3,149.78 × 639
  4. Step 4: Simplify right side
    2,099.85x = 2,012,709.42
  5. Step 5: Solve for x
    x = 2,012,709.42/2,099.85
  6. Step 6: Final answer
    x = 958.50

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Double scale
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Similar ratio
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1.5x scale

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.