Finding the Fourth Proportional to 1,012.63, 1,397.33 and 620.05

Step by Step Solution

1. Step 1: Write the proportion equation
   1,012.63 : 1,397.33 = 620.05 : x
2. Step 2: Convert to fraction form
   1,012.63/1,397.33 = 620.05/x
3. Step 3: Cross multiply
   1,012.63x = 1,397.33 × 620.05
4. Step 4: Simplify right side
   1,012.63x = 866,407.87
5. Step 5: Solve for x
   x = 866,407.87/1,012.63
6. Step 6: Final answer
   x = 855.60