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Finding the Fourth Proportional to 2,138.40, 3,207.60 and 1,213.60

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Solution

The fourth proportional to 2,138.40, 3,207.60 and 1,213.60 is: 1,820.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    2,138.40 : 3,207.60 = 1,213.60 : x
  2. Step 2: Convert to fraction form
    2,138.40/3,207.60 = 1,213.60/x
  3. Step 3: Cross multiply
    2,138.40x = 3,207.60 × 1,213.60
  4. Step 4: Simplify right side
    2,138.40x = 3,892,743.36
  5. Step 5: Solve for x
    x = 3,892,743.36/2,138.40
  6. Step 6: Final answer
    x = 1,820.40

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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.