Finding the Fourth Proportional to 2,415.31, 3,623.78 and 772.09

Step by Step Solution

1. Step 1: Write the proportion equation
   2,415.31 : 3,623.78 = 772.09 : x
2. Step 2: Convert to fraction form
   2,415.31/3,623.78 = 772.09/x
3. Step 3: Cross multiply
   2,415.31x = 3,623.78 × 772.09
4. Step 4: Simplify right side
   2,415.31x = 2,797,884.30
5. Step 5: Solve for x
   x = 2,797,884.30/2,415.31
6. Step 6: Final answer
   x = 1,158.40