Finding the Fourth Proportional to 1,185.90, 1,636.42 and 661.88

Step by Step Solution

1. Step 1: Write the proportion equation
   1,185.90 : 1,636.42 = 661.88 : x
2. Step 2: Convert to fraction form
   1,185.90/1,636.42 = 661.88/x
3. Step 3: Cross multiply
   1,185.90x = 1,636.42 × 661.88
4. Step 4: Simplify right side
   1,185.90x = 1,083,113.67
5. Step 5: Solve for x
   x = 1,083,113.67/1,185.90
6. Step 6: Final answer
   x = 913.33