Finding the Fourth Proportional to 21,811.25, 30,099.93 and 12,380.42

Step by Step Solution

1. Step 1: Write the proportion equation
   21,811.25 : 30,099.93 = 12,380.42 : x
2. Step 2: Convert to fraction form
   21,811.25/30,099.93 = 12,380.42/x
3. Step 3: Cross multiply
   21,811.25x = 30,099.93 × 12,380.42
4. Step 4: Simplify right side
   21,811.25x = 372,649,775.37
5. Step 5: Solve for x
   x = 372,649,775.37/21,811.25
6. Step 6: Final answer
   x = 17,085.21