Finding the Fourth Proportional to 1,388.55, 1,915.76 and 836.55

Step by Step Solution

1. Step 1: Write the proportion equation
   1,388.55 : 1,915.76 = 836.55 : x
2. Step 2: Convert to fraction form
   1,388.55/1,915.76 = 836.55/x
3. Step 3: Cross multiply
   1,388.55x = 1,915.76 × 836.55
4. Step 4: Simplify right side
   1,388.55x = 1,602,629.03
5. Step 5: Solve for x
   x = 1,602,629.03/1,388.55
6. Step 6: Final answer
   x = 1,154.17