Finding the Fourth Proportional to 1,007.02, 1,507.78 and 762.80

Step by Step Solution

1. Step 1: Write the proportion equation
   1,007.02 : 1,507.78 = 762.80 : x
2. Step 2: Convert to fraction form
   1,007.02/1,507.78 = 762.80/x
3. Step 3: Cross multiply
   1,007.02x = 1,507.78 × 762.80
4. Step 4: Simplify right side
   1,007.02x = 1,150,134.58
5. Step 5: Solve for x
   x = 1,150,134.58/1,007.02
6. Step 6: Final answer
   x = 1,142.12