Finding the Fourth Proportional to 1,212.72, 1,674.54 and 988.69

Step by Step Solution

1. Step 1: Write the proportion equation
   1,212.72 : 1,674.54 = 988.69 : x
2. Step 2: Convert to fraction form
   1,212.72/1,674.54 = 988.69/x
3. Step 3: Cross multiply
   1,212.72x = 1,674.54 × 988.69
4. Step 4: Simplify right side
   1,212.72x = 1,655,600.95
5. Step 5: Solve for x
   x = 1,655,600.95/1,212.72
6. Step 6: Final answer
   x = 1,365.20