Finding the Fourth Proportional to 1,185.89, 1,636.56 and 688.64

Step by Step Solution

1. Step 1: Write the proportion equation
   1,185.89 : 1,636.56 = 688.64 : x
2. Step 2: Convert to fraction form
   1,185.89/1,636.56 = 688.64/x
3. Step 3: Cross multiply
   1,185.89x = 1,636.56 × 688.64
4. Step 4: Simplify right side
   1,185.89x = 1,126,992.50
5. Step 5: Solve for x
   x = 1,126,992.50/1,185.89
6. Step 6: Final answer
   x = 950.34