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Finding the Fourth Proportional to 420.44, 579.40 and 399.16

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Solution

The fourth proportional to 420.44, 579.40 and 399.16 is: 550.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.44 : 579.40 = 399.16 : x
  2. Step 2: Convert to fraction form
    420.44/579.40 = 399.16/x
  3. Step 3: Cross multiply
    420.44x = 579.40 × 399.16
  4. Step 4: Simplify right side
    420.44x = 231,273.30
  5. Step 5: Solve for x
    x = 231,273.30/420.44
  6. Step 6: Final answer
    x = 550.07

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.