Finding the Fourth Proportional to 12,784.68, 17,640.90 and 8,075.40

Step by Step Solution

1. Step 1: Write the proportion equation
   12,784.68 : 17,640.90 = 8,075.40 : x
2. Step 2: Convert to fraction form
   12,784.68/17,640.90 = 8,075.40/x
3. Step 3: Cross multiply
   12,784.68x = 17,640.90 × 8,075.40
4. Step 4: Simplify right side
   12,784.68x = 142,457,323.86
5. Step 5: Solve for x
   x = 142,457,323.86/12,784.68
6. Step 6: Final answer
   x = 11,142.81