Finding the Fourth Proportional to 1,012.50, 1,397.31 and 619.60

Step by Step Solution

1. Step 1: Write the proportion equation
   1,012.50 : 1,397.31 = 619.60 : x
2. Step 2: Convert to fraction form
   1,012.50/1,397.31 = 619.60/x
3. Step 3: Cross multiply
   1,012.50x = 1,397.31 × 619.60
4. Step 4: Simplify right side
   1,012.50x = 865,773.28
5. Step 5: Solve for x
   x = 865,773.28/1,012.50
6. Step 6: Final answer
   x = 855.08