Finding the Fourth Proportional to 1,139.02, 1,707.18 and 1,007.80

Step by Step Solution

1. Step 1: Write the proportion equation
   1,139.02 : 1,707.18 = 1,007.80 : x
2. Step 2: Convert to fraction form
   1,139.02/1,707.18 = 1,007.80/x
3. Step 3: Cross multiply
   1,139.02x = 1,707.18 × 1,007.80
4. Step 4: Simplify right side
   1,139.02x = 1,720,496.00
5. Step 5: Solve for x
   x = 1,720,496.00/1,139.02
6. Step 6: Final answer
   x = 1,510.51