Finding the Fourth Proportional to 7,145.78, 10,718.42 and 2,215.31

Step by Step Solution

1. Step 1: Write the proportion equation
   7,145.78 : 10,718.42 = 2,215.31 : x
2. Step 2: Convert to fraction form
   7,145.78/10,718.42 = 2,215.31/x
3. Step 3: Cross multiply
   7,145.78x = 10,718.42 × 2,215.31
4. Step 4: Simplify right side
   7,145.78x = 23,744,558.34
5. Step 5: Solve for x
   x = 23,744,558.34/7,145.78
6. Step 6: Final answer
   x = 3,322.88