Finding the Fourth Proportional to 1,128.48, 1,690.56 and 908.88

Step by Step Solution

1. Step 1: Write the proportion equation
   1,128.48 : 1,690.56 = 908.88 : x
2. Step 2: Convert to fraction form
   1,128.48/1,690.56 = 908.88/x
3. Step 3: Cross multiply
   1,128.48x = 1,690.56 × 908.88
4. Step 4: Simplify right side
   1,128.48x = 1,536,516.17
5. Step 5: Solve for x
   x = 1,536,516.17/1,128.48
6. Step 6: Final answer
   x = 1,361.58