Finding the Fourth Proportional to 21,870.94, 30,181.62 and 12,310.78

Step by Step Solution

1. Step 1: Write the proportion equation
   21,870.94 : 30,181.62 = 12,310.78 : x
2. Step 2: Convert to fraction form
   21,870.94/30,181.62 = 12,310.78/x
3. Step 3: Cross multiply
   21,870.94x = 30,181.62 × 12,310.78
4. Step 4: Simplify right side
   21,870.94x = 371,559,283.86
5. Step 5: Solve for x
   x = 371,559,283.86/21,870.94
6. Step 6: Final answer
   x = 16,988.72