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Finding the Fourth Proportional to 999.64, 1,379.01 and 668.15

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Solution

The fourth proportional to 999.64, 1,379.01 and 668.15 is: 921.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    999.64 : 1,379.01 = 668.15 : x
  2. Step 2: Convert to fraction form
    999.64/1,379.01 = 668.15/x
  3. Step 3: Cross multiply
    999.64x = 1,379.01 × 668.15
  4. Step 4: Simplify right side
    999.64x = 921,375.30
  5. Step 5: Solve for x
    x = 921,375.30/999.64
  6. Step 6: Final answer
    x = 921.71

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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.