Finding the Fourth Proportional to 21,824.75, 30,116.74 and 12,870.20

Step by Step Solution

1. Step 1: Write the proportion equation
   21,824.75 : 30,116.74 = 12,870.20 : x
2. Step 2: Convert to fraction form
   21,824.75/30,116.74 = 12,870.20/x
3. Step 3: Cross multiply
   21,824.75x = 30,116.74 × 12,870.20
4. Step 4: Simplify right side
   21,824.75x = 387,608,467.15
5. Step 5: Solve for x
   x = 387,608,467.15/21,824.75
6. Step 6: Final answer
   x = 17,760.04