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Finding the Fourth Proportional to 390.86, 539.49 and 225.09

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Solution

The fourth proportional to 390.86, 539.49 and 225.09 is: 310.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.86 : 539.49 = 225.09 : x
  2. Step 2: Convert to fraction form
    390.86/539.49 = 225.09/x
  3. Step 3: Cross multiply
    390.86x = 539.49 × 225.09
  4. Step 4: Simplify right side
    390.86x = 121,436.67
  5. Step 5: Solve for x
    x = 121,436.67/390.86
  6. Step 6: Final answer
    x = 310.69

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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.