Finding the Fourth Proportional to 21,290.88, 29,379.18 and 13,113.18

Step by Step Solution

1. Step 1: Write the proportion equation
   21,290.88 : 29,379.18 = 13,113.18 : x
2. Step 2: Convert to fraction form
   21,290.88/29,379.18 = 13,113.18/x
3. Step 3: Cross multiply
   21,290.88x = 29,379.18 × 13,113.18
4. Step 4: Simplify right side
   21,290.88x = 385,254,475.59
5. Step 5: Solve for x
   x = 385,254,475.59/21,290.88
6. Step 6: Final answer
   x = 18,094.81