Finding the Fourth Proportional to 1,280.68, 1,768.52 and 1,211.63

Step by Step Solution

1. Step 1: Write the proportion equation
   1,280.68 : 1,768.52 = 1,211.63 : x
2. Step 2: Convert to fraction form
   1,280.68/1,768.52 = 1,211.63/x
3. Step 3: Cross multiply
   1,280.68x = 1,768.52 × 1,211.63
4. Step 4: Simplify right side
   1,280.68x = 2,142,791.89
5. Step 5: Solve for x
   x = 2,142,791.89/1,280.68
6. Step 6: Final answer
   x = 1,673.17