Finding the Fourth Proportional to 1,512.72, 2,087.56 and 990.16

Step by Step Solution

1. Step 1: Write the proportion equation
   1,512.72 : 2,087.56 = 990.16 : x
2. Step 2: Convert to fraction form
   1,512.72/2,087.56 = 990.16/x
3. Step 3: Cross multiply
   1,512.72x = 2,087.56 × 990.16
4. Step 4: Simplify right side
   1,512.72x = 2,067,018.41
5. Step 5: Solve for x
   x = 2,067,018.41/1,512.72
6. Step 6: Final answer
   x = 1,366.42