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Finding the Fourth Proportional to 1,213.80, 1,819.80 and 391.60

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Solution

The fourth proportional to 1,213.80, 1,819.80 and 391.60 is: 587.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,213.80 : 1,819.80 = 391.60 : x
  2. Step 2: Convert to fraction form
    1,213.80/1,819.80 = 391.60/x
  3. Step 3: Cross multiply
    1,213.80x = 1,819.80 × 391.60
  4. Step 4: Simplify right side
    1,213.80x = 712,633.68
  5. Step 5: Solve for x
    x = 712,633.68/1,213.80
  6. Step 6: Final answer
    x = 587.11

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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.