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Finding the Fourth Proportional to 999.39, 1,378.66 and 668.26

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Solution

The fourth proportional to 999.39, 1,378.66 and 668.26 is: 921.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    999.39 : 1,378.66 = 668.26 : x
  2. Step 2: Convert to fraction form
    999.39/1,378.66 = 668.26/x
  3. Step 3: Cross multiply
    999.39x = 1,378.66 × 668.26
  4. Step 4: Simplify right side
    999.39x = 921,303.33
  5. Step 5: Solve for x
    x = 921,303.33/999.39
  6. Step 6: Final answer
    x = 921.87

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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.