Finding the Fourth Proportional to 1,386.45, 1,912.47 and 1,012.98

Step by Step Solution

1. Step 1: Write the proportion equation
   1,386.45 : 1,912.47 = 1,012.98 : x
2. Step 2: Convert to fraction form
   1,386.45/1,912.47 = 1,012.98/x
3. Step 3: Cross multiply
   1,386.45x = 1,912.47 × 1,012.98
4. Step 4: Simplify right side
   1,386.45x = 1,937,284.30
5. Step 5: Solve for x
   x = 1,937,284.30/1,386.45
6. Step 6: Final answer
   x = 1,397.30