Finding the Fourth Proportional to 21,200.86, 29,256.62 and 12,707.78

Step by Step Solution

1. Step 1: Write the proportion equation
   21,200.86 : 29,256.62 = 12,707.78 : x
2. Step 2: Convert to fraction form
   21,200.86/29,256.62 = 12,707.78/x
3. Step 3: Cross multiply
   21,200.86x = 29,256.62 × 12,707.78
4. Step 4: Simplify right side
   21,200.86x = 371,786,690.50
5. Step 5: Solve for x
   x = 371,786,690.50/21,200.86
6. Step 6: Final answer
   x = 17,536.40