Finding the Fourth Proportional to 899.82, 1,241.91 and 858.78

Step by Step Solution

1. Step 1: Write the proportion equation
   899.82 : 1,241.91 = 858.78 : x
2. Step 2: Convert to fraction form
   899.82/1,241.91 = 858.78/x
3. Step 3: Cross multiply
   899.82x = 1,241.91 × 858.78
4. Step 4: Simplify right side
   899.82x = 1,066,527.47
5. Step 5: Solve for x
   x = 1,066,527.47/899.82
6. Step 6: Final answer
   x = 1,185.27