Finding the Fourth Proportional to 1,212.15, 1,672.58 and 681.06

Step by Step Solution

1. Step 1: Write the proportion equation
   1,212.15 : 1,672.58 = 681.06 : x
2. Step 2: Convert to fraction form
   1,212.15/1,672.58 = 681.06/x
3. Step 3: Cross multiply
   1,212.15x = 1,672.58 × 681.06
4. Step 4: Simplify right side
   1,212.15x = 1,139,127.33
5. Step 5: Solve for x
   x = 1,139,127.33/1,212.15
6. Step 6: Final answer
   x = 939.76