Finding the Fourth Proportional to 20,622.28, 30,911.75 and 13,131.59

Step by Step Solution

1. Step 1: Write the proportion equation
   20,622.28 : 30,911.75 = 13,131.59 : x
2. Step 2: Convert to fraction form
   20,622.28/30,911.75 = 13,131.59/x
3. Step 3: Cross multiply
   20,622.28x = 30,911.75 × 13,131.59
4. Step 4: Simplify right side
   20,622.28x = 405,920,361.52
5. Step 5: Solve for x
   x = 405,920,361.52/20,622.28
6. Step 6: Final answer
   x = 19,683.59