Finding the Fourth Proportional to 21,389.16, 32,021.18 and 12,477.24

Step by Step Solution

1. Step 1: Write the proportion equation
   21,389.16 : 32,021.18 = 12,477.24 : x
2. Step 2: Convert to fraction form
   21,389.16/32,021.18 = 12,477.24/x
3. Step 3: Cross multiply
   21,389.16x = 32,021.18 × 12,477.24
4. Step 4: Simplify right side
   21,389.16x = 399,535,947.94
5. Step 5: Solve for x
   x = 399,535,947.94/21,389.16
6. Step 6: Final answer
   x = 18,679.37