Finding the Fourth Proportional to 1,388.53, 1,915.94 and 828.98

Step by Step Solution

1. Step 1: Write the proportion equation
   1,388.53 : 1,915.94 = 828.98 : x
2. Step 2: Convert to fraction form
   1,388.53/1,915.94 = 828.98/x
3. Step 3: Cross multiply
   1,388.53x = 1,915.94 × 828.98
4. Step 4: Simplify right side
   1,388.53x = 1,588,275.94
5. Step 5: Solve for x
   x = 1,588,275.94/1,388.53
6. Step 6: Final answer
   x = 1,143.85