Finding the Fourth Proportional to 21,153.12, 31,707.68 and 7,102.72

Step by Step Solution

1. Step 1: Write the proportion equation
   21,153.12 : 31,707.68 = 7,102.72 : x
2. Step 2: Convert to fraction form
   21,153.12/31,707.68 = 7,102.72/x
3. Step 3: Cross multiply
   21,153.12x = 31,707.68 × 7,102.72
4. Step 4: Simplify right side
   21,153.12x = 225,210,772.89
5. Step 5: Solve for x
   x = 225,210,772.89/21,153.12
6. Step 6: Final answer
   x = 10,646.69