Finding the Fourth Proportional to 1,515.78, 2,091.78 and 926.76

Step by Step Solution

1. Step 1: Write the proportion equation
   1,515.78 : 2,091.78 = 926.76 : x
2. Step 2: Convert to fraction form
   1,515.78/2,091.78 = 926.76/x
3. Step 3: Cross multiply
   1,515.78x = 2,091.78 × 926.76
4. Step 4: Simplify right side
   1,515.78x = 1,938,578.03
5. Step 5: Solve for x
   x = 1,938,578.03/1,515.78
6. Step 6: Final answer
   x = 1,278.93