Finding the Fourth Proportional to 1,809.86, 2,716.10 and 770.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,809.86 : 2,716.10 = 770.15 : x
2. Step 2: Convert to fraction form
   1,809.86/2,716.10 = 770.15/x
3. Step 3: Cross multiply
   1,809.86x = 2,716.10 × 770.15
4. Step 4: Simplify right side
   1,809.86x = 2,091,797.17
5. Step 5: Solve for x
   x = 2,091,797.17/1,809.86
6. Step 6: Final answer
   x = 1,155.78