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Finding the Fourth Proportional to 919.88, 1,379.04 and 399.49

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Solution

The fourth proportional to 919.88, 1,379.04 and 399.49 is: 598.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    919.88 : 1,379.04 = 399.49 : x
  2. Step 2: Convert to fraction form
    919.88/1,379.04 = 399.49/x
  3. Step 3: Cross multiply
    919.88x = 1,379.04 × 399.49
  4. Step 4: Simplify right side
    919.88x = 550,905.79
  5. Step 5: Solve for x
    x = 550,905.79/919.88
  6. Step 6: Final answer
    x = 598.89

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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.