Finding the Fourth Proportional to 21,645.30, 29,870.73 and 12,698.10

Step by Step Solution

1. Step 1: Write the proportion equation
   21,645.30 : 29,870.73 = 12,698.10 : x
2. Step 2: Convert to fraction form
   21,645.30/29,870.73 = 12,698.10/x
3. Step 3: Cross multiply
   21,645.30x = 29,870.73 × 12,698.10
4. Step 4: Simplify right side
   21,645.30x = 379,301,516.61
5. Step 5: Solve for x
   x = 379,301,516.61/21,645.30
6. Step 6: Final answer
   x = 17,523.50