Finding the Fourth Proportional to 2,128.58, 3,191.82 and 667.72

Step by Step Solution

1. Step 1: Write the proportion equation
   2,128.58 : 3,191.82 = 667.72 : x
2. Step 2: Convert to fraction form
   2,128.58/3,191.82 = 667.72/x
3. Step 3: Cross multiply
   2,128.58x = 3,191.82 × 667.72
4. Step 4: Simplify right side
   2,128.58x = 2,131,242.05
5. Step 5: Solve for x
   x = 2,131,242.05/2,128.58
6. Step 6: Final answer
   x = 1,001.25