Finding the Fourth Proportional to 1,189.43, 1,640.83 and 770.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,189.43 : 1,640.83 = 770.15 : x
2. Step 2: Convert to fraction form
   1,189.43/1,640.83 = 770.15/x
3. Step 3: Cross multiply
   1,189.43x = 1,640.83 × 770.15
4. Step 4: Simplify right side
   1,189.43x = 1,263,679.47
5. Step 5: Solve for x
   x = 1,263,679.47/1,189.43
6. Step 6: Final answer
   x = 1,062.42