Finding the Fourth Proportional to 12,979.01, 17,919.59 and 9,989.57

Step by Step Solution

1. Step 1: Write the proportion equation
   12,979.01 : 17,919.59 = 9,989.57 : x
2. Step 2: Convert to fraction form
   12,979.01/17,919.59 = 9,989.57/x
3. Step 3: Cross multiply
   12,979.01x = 17,919.59 × 9,989.57
4. Step 4: Simplify right side
   12,979.01x = 179,008,948.73
5. Step 5: Solve for x
   x = 179,008,948.73/12,979.01
6. Step 6: Final answer
   x = 13,792.19