Finding the Fourth Proportional to 2,141.67, 3,212.90 and 660.86

Step by Step Solution

1. Step 1: Write the proportion equation
   2,141.67 : 3,212.90 = 660.86 : x
2. Step 2: Convert to fraction form
   2,141.67/3,212.90 = 660.86/x
3. Step 3: Cross multiply
   2,141.67x = 3,212.90 × 660.86
4. Step 4: Simplify right side
   2,141.67x = 2,123,272.25
5. Step 5: Solve for x
   x = 2,123,272.25/2,141.67
6. Step 6: Final answer
   x = 991.41