Finding the Fourth Proportional to 2,128.42, 3,191.38 and 828.36

Step by Step Solution

1. Step 1: Write the proportion equation
   2,128.42 : 3,191.38 = 828.36 : x
2. Step 2: Convert to fraction form
   2,128.42/3,191.38 = 828.36/x
3. Step 3: Cross multiply
   2,128.42x = 3,191.38 × 828.36
4. Step 4: Simplify right side
   2,128.42x = 2,643,611.54
5. Step 5: Solve for x
   x = 2,643,611.54/2,128.42
6. Step 6: Final answer
   x = 1,242.05