Finding the Fourth Proportional to 2,128.86, 3,193.56 and 813.42

Step by Step Solution

1. Step 1: Write the proportion equation
   2,128.86 : 3,193.56 = 813.42 : x
2. Step 2: Convert to fraction form
   2,128.86/3,193.56 = 813.42/x
3. Step 3: Cross multiply
   2,128.86x = 3,193.56 × 813.42
4. Step 4: Simplify right side
   2,128.86x = 2,597,705.58
5. Step 5: Solve for x
   x = 2,597,705.58/2,128.86
6. Step 6: Final answer
   x = 1,220.23