Finding the Fourth Proportional to 13,139.82, 19,733.22 and 12,611.28

Step by Step Solution

1. Step 1: Write the proportion equation
   13,139.82 : 19,733.22 = 12,611.28 : x
2. Step 2: Convert to fraction form
   13,139.82/19,733.22 = 12,611.28/x
3. Step 3: Cross multiply
   13,139.82x = 19,733.22 × 12,611.28
4. Step 4: Simplify right side
   13,139.82x = 248,861,162.72
5. Step 5: Solve for x
   x = 248,861,162.72/13,139.82
6. Step 6: Final answer
   x = 18,939.47