Finding the Fourth Proportional to 21,981.68, 30,329.34 and 13,031.30

Step by Step Solution

1. Step 1: Write the proportion equation
   21,981.68 : 30,329.34 = 13,031.30 : x
2. Step 2: Convert to fraction form
   21,981.68/30,329.34 = 13,031.30/x
3. Step 3: Cross multiply
   21,981.68x = 30,329.34 × 13,031.30
4. Step 4: Simplify right side
   21,981.68x = 395,230,728.34
5. Step 5: Solve for x
   x = 395,230,728.34/21,981.68
6. Step 6: Final answer
   x = 17,980.01