Finding the Fourth Proportional to 1,012.15, 1,515.77 and 577.99

Step by Step Solution

1. Step 1: Write the proportion equation
   1,012.15 : 1,515.77 = 577.99 : x
2. Step 2: Convert to fraction form
   1,012.15/1,515.77 = 577.99/x
3. Step 3: Cross multiply
   1,012.15x = 1,515.77 × 577.99
4. Step 4: Simplify right side
   1,012.15x = 876,089.43
5. Step 5: Solve for x
   x = 876,089.43/1,012.15
6. Step 6: Final answer
   x = 865.58