Finding the Fourth Proportional to 1,786.51, 2,465.31 and 989.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,786.51 : 2,465.31 = 989.78 : x
2. Step 2: Convert to fraction form
   1,786.51/2,465.31 = 989.78/x
3. Step 3: Cross multiply
   1,786.51x = 2,465.31 × 989.78
4. Step 4: Simplify right side
   1,786.51x = 2,440,114.53
5. Step 5: Solve for x
   x = 2,440,114.53/1,786.51
6. Step 6: Final answer
   x = 1,365.86