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Finding the Fourth Proportional to 664.86, 917.40 and 399.30

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Solution

The fourth proportional to 664.86, 917.40 and 399.30 is: 550.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    664.86 : 917.40 = 399.30 : x
  2. Step 2: Convert to fraction form
    664.86/917.40 = 399.30/x
  3. Step 3: Cross multiply
    664.86x = 917.40 × 399.30
  4. Step 4: Simplify right side
    664.86x = 366,317.82
  5. Step 5: Solve for x
    x = 366,317.82/664.86
  6. Step 6: Final answer
    x = 550.97

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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.