Finding the Fourth Proportional to 2,007.80, 3,012.06 and 621.13

Step by Step Solution

1. Step 1: Write the proportion equation
   2,007.80 : 3,012.06 = 621.13 : x
2. Step 2: Convert to fraction form
   2,007.80/3,012.06 = 621.13/x
3. Step 3: Cross multiply
   2,007.80x = 3,012.06 × 621.13
4. Step 4: Simplify right side
   2,007.80x = 1,870,880.83
5. Step 5: Solve for x
   x = 1,870,880.83/2,007.80
6. Step 6: Final answer
   x = 931.81