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Finding the Fourth Proportional to 479.72, 662.12 and 391.78

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Solution

The fourth proportional to 479.72, 662.12 and 391.78 is: 540.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    479.72 : 662.12 = 391.78 : x
  2. Step 2: Convert to fraction form
    479.72/662.12 = 391.78/x
  3. Step 3: Cross multiply
    479.72x = 662.12 × 391.78
  4. Step 4: Simplify right side
    479.72x = 259,405.37
  5. Step 5: Solve for x
    x = 259,405.37/479.72
  6. Step 6: Final answer
    x = 540.74

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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.