Finding the Fourth Proportional to 21,860.16, 30,170.52 and 12,431.76

Step by Step Solution

1. Step 1: Write the proportion equation
   21,860.16 : 30,170.52 = 12,431.76 : x
2. Step 2: Convert to fraction form
   21,860.16/30,170.52 = 12,431.76/x
3. Step 3: Cross multiply
   21,860.16x = 30,170.52 × 12,431.76
4. Step 4: Simplify right side
   21,860.16x = 375,072,663.72
5. Step 5: Solve for x
   x = 375,072,663.72/21,860.16
6. Step 6: Final answer
   x = 17,157.82