Finding the Fourth Proportional to 21,388.89, 29,502.76 and 13,720.02

Step by Step Solution

1. Step 1: Write the proportion equation
   21,388.89 : 29,502.76 = 13,720.02 : x
2. Step 2: Convert to fraction form
   21,388.89/29,502.76 = 13,720.02/x
3. Step 3: Cross multiply
   21,388.89x = 29,502.76 × 13,720.02
4. Step 4: Simplify right side
   21,388.89x = 404,778,559.32
5. Step 5: Solve for x
   x = 404,778,559.32/21,388.89
6. Step 6: Final answer
   x = 18,924.71