Finding the Fourth Proportional to 12,128.56, 16,734.90 and 7,091.80

Step by Step Solution

1. Step 1: Write the proportion equation
   12,128.56 : 16,734.90 = 7,091.80 : x
2. Step 2: Convert to fraction form
   12,128.56/16,734.90 = 7,091.80/x
3. Step 3: Cross multiply
   12,128.56x = 16,734.90 × 7,091.80
4. Step 4: Simplify right side
   12,128.56x = 118,680,563.82
5. Step 5: Solve for x
   x = 118,680,563.82/12,128.56
6. Step 6: Final answer
   x = 9,785.21