Finding the Fourth Proportional to 8,685.72, 13,003.59 and 7,784.19

Step by Step Solution

1. Step 1: Write the proportion equation
   8,685.72 : 13,003.59 = 7,784.19 : x
2. Step 2: Convert to fraction form
   8,685.72/13,003.59 = 7,784.19/x
3. Step 3: Cross multiply
   8,685.72x = 13,003.59 × 7,784.19
4. Step 4: Simplify right side
   8,685.72x = 101,222,415.24
5. Step 5: Solve for x
   x = 101,222,415.24/8,685.72
6. Step 6: Final answer
   x = 11,653.89