Finding the Fourth Proportional to 21,619.78, 29,838.17 and 12,670.83

Step by Step Solution

1. Step 1: Write the proportion equation
   21,619.78 : 29,838.17 = 12,670.83 : x
2. Step 2: Convert to fraction form
   21,619.78/29,838.17 = 12,670.83/x
3. Step 3: Cross multiply
   21,619.78x = 29,838.17 × 12,670.83
4. Step 4: Simplify right side
   21,619.78x = 378,074,411.26
5. Step 5: Solve for x
   x = 378,074,411.26/21,619.78
6. Step 6: Final answer
   x = 17,487.43