Finding the Fourth Proportional to 1,085.58, 1,626.21 and 776.57

Step by Step Solution

1. Step 1: Write the proportion equation
   1,085.58 : 1,626.21 = 776.57 : x
2. Step 2: Convert to fraction form
   1,085.58/1,626.21 = 776.57/x
3. Step 3: Cross multiply
   1,085.58x = 1,626.21 × 776.57
4. Step 4: Simplify right side
   1,085.58x = 1,262,857.77
5. Step 5: Solve for x
   x = 1,262,857.77/1,085.58
6. Step 6: Final answer
   x = 1,163.30