Finding the Fourth Proportional to 1,216.89, 1,823.80 and 777.98

Step by Step Solution

1. Step 1: Write the proportion equation
   1,216.89 : 1,823.80 = 777.98 : x
2. Step 2: Convert to fraction form
   1,216.89/1,823.80 = 777.98/x
3. Step 3: Cross multiply
   1,216.89x = 1,823.80 × 777.98
4. Step 4: Simplify right side
   1,216.89x = 1,418,868.86
5. Step 5: Solve for x
   x = 1,418,868.86/1,216.89
6. Step 6: Final answer
   x = 1,165.98