Finding the Fourth Proportional to 21,788.16, 32,664.96 and 7,929.60

Step by Step Solution

1. Step 1: Write the proportion equation
   21,788.16 : 32,664.96 = 7,929.60 : x
2. Step 2: Convert to fraction form
   21,788.16/32,664.96 = 7,929.60/x
3. Step 3: Cross multiply
   21,788.16x = 32,664.96 × 7,929.60
4. Step 4: Simplify right side
   21,788.16x = 259,020,066.82
5. Step 5: Solve for x
   x = 259,020,066.82/21,788.16
6. Step 6: Final answer
   x = 11,888.11