Well you would first add 5/13 and 2/13, so 7/13. Then you would subtract 7 from 13. So your answer would be 6/13. Hope that helped!
It would be: 11 * 90/100
= 11 * 0.90 = 9.9
So, your final answer is 9.9
Hope this helps!
Truee is right you got it dude
Area of triangle=1/2bh
Area=248ft
Base=x
Height=2x-1
248=1/2×x×(2x-1)........