Finding the Fourth Proportional to 2,790.32, 4,179.60 and 1,328.00

Step by Step Solution

1. Step 1: Write the proportion equation
   2,790.32 : 4,179.60 = 1,328.00 : x
2. Step 2: Convert to fraction form
   2,790.32/4,179.60 = 1,328.00/x
3. Step 3: Cross multiply
   2,790.32x = 4,179.60 × 1,328.00
4. Step 4: Simplify right side
   2,790.32x = 5,550,487.90
5. Step 5: Solve for x
   x = 5,550,487.90/2,790.32
6. Step 6: Final answer
   x = 1,989.20