Finding the Fourth Proportional to 1,160.79, 1,601.91 and 636.81

Step by Step Solution

1. Step 1: Write the proportion equation
   1,160.79 : 1,601.91 = 636.81 : x
2. Step 2: Convert to fraction form
   1,160.79/1,601.91 = 636.81/x
3. Step 3: Cross multiply
   1,160.79x = 1,601.91 × 636.81
4. Step 4: Simplify right side
   1,160.79x = 1,020,112.31
5. Step 5: Solve for x
   x = 1,020,112.31/1,160.79
6. Step 6: Final answer
   x = 878.81