Finding the Fourth Proportional to 2,215.16, 3,320.76 and 915.80

Step by Step Solution

1. Step 1: Write the proportion equation
   2,215.16 : 3,320.76 = 915.80 : x
2. Step 2: Convert to fraction form
   2,215.16/3,320.76 = 915.80/x
3. Step 3: Cross multiply
   2,215.16x = 3,320.76 × 915.80
4. Step 4: Simplify right side
   2,215.16x = 3,041,152.01
5. Step 5: Solve for x
   x = 3,041,152.01/2,215.16
6. Step 6: Final answer
   x = 1,372.88