Finding the Fourth Proportional to 1,158.69, 1,736.94 and 428.07

Step by Step Solution

1. Step 1: Write the proportion equation
   1,158.69 : 1,736.94 = 428.07 : x
2. Step 2: Convert to fraction form
   1,158.69/1,736.94 = 428.07/x
3. Step 3: Cross multiply
   1,158.69x = 1,736.94 × 428.07
4. Step 4: Simplify right side
   1,158.69x = 743,531.91
5. Step 5: Solve for x
   x = 743,531.91/1,158.69
6. Step 6: Final answer
   x = 641.70