Finding the Fourth Proportional to 21,012.42, 31,528.20 and 7,865.82

Step by Step Solution

1. Step 1: Write the proportion equation
   21,012.42 : 31,528.20 = 7,865.82 : x
2. Step 2: Convert to fraction form
   21,012.42/31,528.20 = 7,865.82/x
3. Step 3: Cross multiply
   21,012.42x = 31,528.20 × 7,865.82
4. Step 4: Simplify right side
   21,012.42x = 247,995,175.62
5. Step 5: Solve for x
   x = 247,995,175.62/21,012.42
6. Step 6: Final answer
   x = 11,802.31