Finding the Fourth Proportional to 1,188.01, 1,782.69 and 640.18

Step by Step Solution

1. Step 1: Write the proportion equation
   1,188.01 : 1,782.69 = 640.18 : x
2. Step 2: Convert to fraction form
   1,188.01/1,782.69 = 640.18/x
3. Step 3: Cross multiply
   1,188.01x = 1,782.69 × 640.18
4. Step 4: Simplify right side
   1,188.01x = 1,141,242.48
5. Step 5: Solve for x
   x = 1,141,242.48/1,188.01
6. Step 6: Final answer
   x = 960.63