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Finding the Fourth Proportional to 919.65, 1,379.49 and 399.63

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Solution

The fourth proportional to 919.65, 1,379.49 and 399.63 is: 599.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    919.65 : 1,379.49 = 399.63 : x
  2. Step 2: Convert to fraction form
    919.65/1,379.49 = 399.63/x
  3. Step 3: Cross multiply
    919.65x = 1,379.49 × 399.63
  4. Step 4: Simplify right side
    919.65x = 551,285.59
  5. Step 5: Solve for x
    x = 551,285.59/919.65
  6. Step 6: Final answer
    x = 599.45

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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.