Finding the Fourth Proportional to 21,150.32, 31,720.88 and 8,667.12

Step by Step Solution

1. Step 1: Write the proportion equation
   21,150.32 : 31,720.88 = 8,667.12 : x
2. Step 2: Convert to fraction form
   21,150.32/31,720.88 = 8,667.12/x
3. Step 3: Cross multiply
   21,150.32x = 31,720.88 × 8,667.12
4. Step 4: Simplify right side
   21,150.32x = 274,928,673.47
5. Step 5: Solve for x
   x = 274,928,673.47/21,150.32
6. Step 6: Final answer
   x = 12,998.79