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Finding the Fourth Proportional to 664.49, 995.92 and 390.78

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Solution

The fourth proportional to 664.49, 995.92 and 390.78 is: 585.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    664.49 : 995.92 = 390.78 : x
  2. Step 2: Convert to fraction form
    664.49/995.92 = 390.78/x
  3. Step 3: Cross multiply
    664.49x = 995.92 × 390.78
  4. Step 4: Simplify right side
    664.49x = 389,185.62
  5. Step 5: Solve for x
    x = 389,185.62/664.49
  6. Step 6: Final answer
    x = 585.69

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.