Finding the Fourth Proportional to 1,212.51, 1,673.27 and 688.55

Step by Step Solution

1. Step 1: Write the proportion equation
   1,212.51 : 1,673.27 = 688.55 : x
2. Step 2: Convert to fraction form
   1,212.51/1,673.27 = 688.55/x
3. Step 3: Cross multiply
   1,212.51x = 1,673.27 × 688.55
4. Step 4: Simplify right side
   1,212.51x = 1,152,120.83
5. Step 5: Solve for x
   x = 1,152,120.83/1,212.51
6. Step 6: Final answer
   x = 950.19