Finding the Fourth Proportional to 21,105.12, 31,659.36 and 7,065.21

Step by Step Solution

1. Step 1: Write the proportion equation
   21,105.12 : 31,659.36 = 7,065.21 : x
2. Step 2: Convert to fraction form
   21,105.12/31,659.36 = 7,065.21/x
3. Step 3: Cross multiply
   21,105.12x = 31,659.36 × 7,065.21
4. Step 4: Simplify right side
   21,105.12x = 223,680,026.87
5. Step 5: Solve for x
   x = 223,680,026.87/21,105.12
6. Step 6: Final answer
   x = 10,598.38