Finding the Fourth Proportional to 1,116.72, 1,541.52 and 921.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,116.72 : 1,541.52 = 921.12 : x
2. Step 2: Convert to fraction form
   1,116.72/1,541.52 = 921.12/x
3. Step 3: Cross multiply
   1,116.72x = 1,541.52 × 921.12
4. Step 4: Simplify right side
   1,116.72x = 1,419,924.90
5. Step 5: Solve for x
   x = 1,419,924.90/1,116.72
6. Step 6: Final answer
   x = 1,271.51