Finding the Fourth Proportional to 21,420.58, 32,139.75 and 13,100.89

Step by Step Solution

1. Step 1: Write the proportion equation
   21,420.58 : 32,139.75 = 13,100.89 : x
2. Step 2: Convert to fraction form
   21,420.58/32,139.75 = 13,100.89/x
3. Step 3: Cross multiply
   21,420.58x = 32,139.75 × 13,100.89
4. Step 4: Simplify right side
   21,420.58x = 421,059,168.68
5. Step 5: Solve for x
   x = 421,059,168.68/21,420.58
6. Step 6: Final answer
   x = 19,656.76