Finding the Fourth Proportional to 2,783.28, 4,172.50 and 1,138.78

Step by Step Solution

1. Step 1: Write the proportion equation
   2,783.28 : 4,172.50 = 1,138.78 : x
2. Step 2: Convert to fraction form
   2,783.28/4,172.50 = 1,138.78/x
3. Step 3: Cross multiply
   2,783.28x = 4,172.50 × 1,138.78
4. Step 4: Simplify right side
   2,783.28x = 4,751,536.31
5. Step 5: Solve for x
   x = 4,751,536.31/2,783.28
6. Step 6: Final answer
   x = 1,707.17