Finding the Fourth Proportional to 21,151.05, 31,539.83 and 20,961.24

Step by Step Solution

1. Step 1: Write the proportion equation
   21,151.05 : 31,539.83 = 20,961.24 : x
2. Step 2: Convert to fraction form
   21,151.05/31,539.83 = 20,961.24/x
3. Step 3: Cross multiply
   21,151.05x = 31,539.83 × 20,961.24
4. Step 4: Simplify right side
   21,151.05x = 661,113,946.19
5. Step 5: Solve for x
   x = 661,113,946.19/21,151.05
6. Step 6: Final answer
   x = 31,256.79