Finding the Fourth Proportional to 21,647.69, 29,878.78 and 12,698.07

Step by Step Solution

1. Step 1: Write the proportion equation
   21,647.69 : 29,878.78 = 12,698.07 : x
2. Step 2: Convert to fraction form
   21,647.69/29,878.78 = 12,698.07/x
3. Step 3: Cross multiply
   21,647.69x = 29,878.78 × 12,698.07
4. Step 4: Simplify right side
   21,647.69x = 379,402,839.95
5. Step 5: Solve for x
   x = 379,402,839.95/21,647.69
6. Step 6: Final answer
   x = 17,526.25