Finding the Fourth Proportional to 1,336.79, 1,991.85 and 1,191.30

Step by Step Solution

1. Step 1: Write the proportion equation
   1,336.79 : 1,991.85 = 1,191.30 : x
2. Step 2: Convert to fraction form
   1,336.79/1,991.85 = 1,191.30/x
3. Step 3: Cross multiply
   1,336.79x = 1,991.85 × 1,191.30
4. Step 4: Simplify right side
   1,336.79x = 2,372,895.37
5. Step 5: Solve for x
   x = 2,372,895.37/1,336.79
6. Step 6: Final answer
   x = 1,775.08