Finding the Fourth Proportional to 8,990.72, 12,407.25 and 5,216.13

Step by Step Solution

1. Step 1: Write the proportion equation
   8,990.72 : 12,407.25 = 5,216.13 : x
2. Step 2: Convert to fraction form
   8,990.72/12,407.25 = 5,216.13/x
3. Step 3: Cross multiply
   8,990.72x = 12,407.25 × 5,216.13
4. Step 4: Simplify right side
   8,990.72x = 64,717,828.94
5. Step 5: Solve for x
   x = 64,717,828.94/8,990.72
6. Step 6: Final answer
   x = 7,198.29