Finding the Fourth Proportional to 2,215.02, 3,321.32 and 915.78

Step by Step Solution

1. Step 1: Write the proportion equation
   2,215.02 : 3,321.32 = 915.78 : x
2. Step 2: Convert to fraction form
   2,215.02/3,321.32 = 915.78/x
3. Step 3: Cross multiply
   2,215.02x = 3,321.32 × 915.78
4. Step 4: Simplify right side
   2,215.02x = 3,041,598.43
5. Step 5: Solve for x
   x = 3,041,598.43/2,215.02
6. Step 6: Final answer
   x = 1,373.17