Finding the Fourth Proportional to 1,188.61, 1,640.31 and 716.52

Step by Step Solution

1. Step 1: Write the proportion equation
   1,188.61 : 1,640.31 = 716.52 : x
2. Step 2: Convert to fraction form
   1,188.61/1,640.31 = 716.52/x
3. Step 3: Cross multiply
   1,188.61x = 1,640.31 × 716.52
4. Step 4: Simplify right side
   1,188.61x = 1,175,310.82
5. Step 5: Solve for x
   x = 1,175,310.82/1,188.61
6. Step 6: Final answer
   x = 988.81