Finding the Fourth Proportional to 12,916.87, 17,820.69 and 8,443.20

Step by Step Solution

1. Step 1: Write the proportion equation
   12,916.87 : 17,820.69 = 8,443.20 : x
2. Step 2: Convert to fraction form
   12,916.87/17,820.69 = 8,443.20/x
3. Step 3: Cross multiply
   12,916.87x = 17,820.69 × 8,443.20
4. Step 4: Simplify right side
   12,916.87x = 150,463,649.81
5. Step 5: Solve for x
   x = 150,463,649.81/12,916.87
6. Step 6: Final answer
   x = 11,648.62