Finding the Fourth Proportional to 1,810.79, 2,715.62 and 770.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,810.79 : 2,715.62 = 770.78 : x
2. Step 2: Convert to fraction form
   1,810.79/2,715.62 = 770.78/x
3. Step 3: Cross multiply
   1,810.79x = 2,715.62 × 770.78
4. Step 4: Simplify right side
   1,810.79x = 2,093,128.15
5. Step 5: Solve for x
   x = 2,093,128.15/1,810.79
6. Step 6: Final answer
   x = 1,155.92