Finding the Fourth Proportional to 2,012.81, 3,019.32 and 780.12

Step by Step Solution

1. Step 1: Write the proportion equation
   2,012.81 : 3,019.32 = 780.12 : x
2. Step 2: Convert to fraction form
   2,012.81/3,019.32 = 780.12/x
3. Step 3: Cross multiply
   2,012.81x = 3,019.32 × 780.12
4. Step 4: Simplify right side
   2,012.81x = 2,355,431.92
5. Step 5: Solve for x
   x = 2,355,431.92/2,012.81
6. Step 6: Final answer
   x = 1,170.22