Finding the Fourth Proportional to 1,510.90, 2,085.27 and 921.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,510.90 : 2,085.27 = 921.78 : x
2. Step 2: Convert to fraction form
   1,510.90/2,085.27 = 921.78/x
3. Step 3: Cross multiply
   1,510.90x = 2,085.27 × 921.78
4. Step 4: Simplify right side
   1,510.90x = 1,922,148.90
5. Step 5: Solve for x
   x = 1,922,148.90/1,510.90
6. Step 6: Final answer
   x = 1,272.19