Finding the Fourth Proportional to 21,865.08, 30,159.72 and 12,912.03

Step by Step Solution

1. Step 1: Write the proportion equation
   21,865.08 : 30,159.72 = 12,912.03 : x
2. Step 2: Convert to fraction form
   21,865.08/30,159.72 = 12,912.03/x
3. Step 3: Cross multiply
   21,865.08x = 30,159.72 × 12,912.03
4. Step 4: Simplify right side
   21,865.08x = 389,423,209.43
5. Step 5: Solve for x
   x = 389,423,209.43/21,865.08
6. Step 6: Final answer
   x = 17,810.28