Finding the Fourth Proportional to 1,213.69, 1,674.89 and 661.69

Step by Step Solution

1. Step 1: Write the proportion equation
   1,213.69 : 1,674.89 = 661.69 : x
2. Step 2: Convert to fraction form
   1,213.69/1,674.89 = 661.69/x
3. Step 3: Cross multiply
   1,213.69x = 1,674.89 × 661.69
4. Step 4: Simplify right side
   1,213.69x = 1,108,252.95
5. Step 5: Solve for x
   x = 1,108,252.95/1,213.69
6. Step 6: Final answer
   x = 913.13