Finding the Fourth Proportional to 15,635.77, 21,580.71 and 9,969.21

Step by Step Solution

1. Step 1: Write the proportion equation
   15,635.77 : 21,580.71 = 9,969.21 : x
2. Step 2: Convert to fraction form
   15,635.77/21,580.71 = 9,969.21/x
3. Step 3: Cross multiply
   15,635.77x = 21,580.71 × 9,969.21
4. Step 4: Simplify right side
   15,635.77x = 215,142,629.94
5. Step 5: Solve for x
   x = 215,142,629.94/15,635.77
6. Step 6: Final answer
   x = 13,759.65