Finding the Fourth Proportional to 2,990.72, 4,486.25 and 910.80

Step by Step Solution

1. Step 1: Write the proportion equation
   2,990.72 : 4,486.25 = 910.80 : x
2. Step 2: Convert to fraction form
   2,990.72/4,486.25 = 910.80/x
3. Step 3: Cross multiply
   2,990.72x = 4,486.25 × 910.80
4. Step 4: Simplify right side
   2,990.72x = 4,086,076.50
5. Step 5: Solve for x
   x = 4,086,076.50/2,990.72
6. Step 6: Final answer
   x = 1,366.25