Finding the Fourth Proportional to 1,211.94, 1,817.55 and 772.55

Step by Step Solution

1. Step 1: Write the proportion equation
   1,211.94 : 1,817.55 = 772.55 : x
2. Step 2: Convert to fraction form
   1,211.94/1,817.55 = 772.55/x
3. Step 3: Cross multiply
   1,211.94x = 1,817.55 × 772.55
4. Step 4: Simplify right side
   1,211.94x = 1,404,139.16
5. Step 5: Solve for x
   x = 1,404,139.16/1,211.94
6. Step 6: Final answer
   x = 1,158.59