Finding the Fourth Proportional to 21,915.53, 30,243.35 and 12,485.69

Step by Step Solution

1. Step 1: Write the proportion equation
   21,915.53 : 30,243.35 = 12,485.69 : x
2. Step 2: Convert to fraction form
   21,915.53/30,243.35 = 12,485.69/x
3. Step 3: Cross multiply
   21,915.53x = 30,243.35 × 12,485.69
4. Step 4: Simplify right side
   21,915.53x = 377,608,972.66
5. Step 5: Solve for x
   x = 377,608,972.66/21,915.53
6. Step 6: Final answer
   x = 17,230.20