Finding the Fourth Proportional to 1,120.80, 1,672.72 and 1,091.64

Step by Step Solution

1. Step 1: Write the proportion equation
   1,120.80 : 1,672.72 = 1,091.64 : x
2. Step 2: Convert to fraction form
   1,120.80/1,672.72 = 1,091.64/x
3. Step 3: Cross multiply
   1,120.80x = 1,672.72 × 1,091.64
4. Step 4: Simplify right side
   1,120.80x = 1,826,008.34
5. Step 5: Solve for x
   x = 1,826,008.34/1,120.80
6. Step 6: Final answer
   x = 1,629.20