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Finding the Fourth Proportional to 998.96, 1,379.64 and 668.78

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Solution

The fourth proportional to 998.96, 1,379.64 and 668.78 is: 923.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    998.96 : 1,379.64 = 668.78 : x
  2. Step 2: Convert to fraction form
    998.96/1,379.64 = 668.78/x
  3. Step 3: Cross multiply
    998.96x = 1,379.64 × 668.78
  4. Step 4: Simplify right side
    998.96x = 922,675.64
  5. Step 5: Solve for x
    x = 922,675.64/998.96
  6. Step 6: Final answer
    x = 923.64

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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.