Finding the Fourth Proportional to 1,190.69, 1,643.15 and 666.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,190.69 : 1,643.15 = 666.72 : x
2. Step 2: Convert to fraction form
   1,190.69/1,643.15 = 666.72/x
3. Step 3: Cross multiply
   1,190.69x = 1,643.15 × 666.72
4. Step 4: Simplify right side
   1,190.69x = 1,095,520.97
5. Step 5: Solve for x
   x = 1,095,520.97/1,190.69
6. Step 6: Final answer
   x = 920.07