Finding the Fourth Proportional to 1,222.47, 1,685.53 and 1,012.88

Step by Step Solution

1. Step 1: Write the proportion equation
   1,222.47 : 1,685.53 = 1,012.88 : x
2. Step 2: Convert to fraction form
   1,222.47/1,685.53 = 1,012.88/x
3. Step 3: Cross multiply
   1,222.47x = 1,685.53 × 1,012.88
4. Step 4: Simplify right side
   1,222.47x = 1,707,239.63
5. Step 5: Solve for x
   x = 1,707,239.63/1,222.47
6. Step 6: Final answer
   x = 1,396.55