Finding the Fourth Proportional to 21,390.60, 29,511.50 and 12,436.05

Step by Step Solution

1. Step 1: Write the proportion equation
   21,390.60 : 29,511.50 = 12,436.05 : x
2. Step 2: Convert to fraction form
   21,390.60/29,511.50 = 12,436.05/x
3. Step 3: Cross multiply
   21,390.60x = 29,511.50 × 12,436.05
4. Step 4: Simplify right side
   21,390.60x = 367,006,427.39
5. Step 5: Solve for x
   x = 367,006,427.39/21,390.60
6. Step 6: Final answer
   x = 17,157.37