Finding the Fourth Proportional to 1,222.82, 1,686.93 and 780.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,222.82 : 1,686.93 = 780.50 : x
2. Step 2: Convert to fraction form
   1,222.82/1,686.93 = 780.50/x
3. Step 3: Cross multiply
   1,222.82x = 1,686.93 × 780.50
4. Step 4: Simplify right side
   1,222.82x = 1,316,648.87
5. Step 5: Solve for x
   x = 1,316,648.87/1,222.82
6. Step 6: Final answer
   x = 1,076.73