Finding the Fourth Proportional to 1,016.78, 1,516.42 and 918.36

Step by Step Solution

1. Step 1: Write the proportion equation
   1,016.78 : 1,516.42 = 918.36 : x
2. Step 2: Convert to fraction form
   1,016.78/1,516.42 = 918.36/x
3. Step 3: Cross multiply
   1,016.78x = 1,516.42 × 918.36
4. Step 4: Simplify right side
   1,016.78x = 1,392,619.47
5. Step 5: Solve for x
   x = 1,392,619.47/1,016.78
6. Step 6: Final answer
   x = 1,369.64