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Finding the Fourth Proportional to 479.64, 660.78 and 391.80

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Solution

The fourth proportional to 479.64, 660.78 and 391.80 is: 539.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    479.64 : 660.78 = 391.80 : x
  2. Step 2: Convert to fraction form
    479.64/660.78 = 391.80/x
  3. Step 3: Cross multiply
    479.64x = 660.78 × 391.80
  4. Step 4: Simplify right side
    479.64x = 258,893.60
  5. Step 5: Solve for x
    x = 258,893.60/479.64
  6. Step 6: Final answer
    x = 539.77

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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.