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Finding the Fourth Proportional to 919.89, 1,380.36 and 399.77

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Solution

The fourth proportional to 919.89, 1,380.36 and 399.77 is: 599.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    919.89 : 1,380.36 = 399.77 : x
  2. Step 2: Convert to fraction form
    919.89/1,380.36 = 399.77/x
  3. Step 3: Cross multiply
    919.89x = 1,380.36 × 399.77
  4. Step 4: Simplify right side
    919.89x = 551,819.62
  5. Step 5: Solve for x
    x = 551,819.62/919.89
  6. Step 6: Final answer
    x = 599.88

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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.