Verified Answer :

This is for #11 and #12. 

First lets find the lateral area of each triangle. We will use the
following formula:-







lateral area = 4 (1/2 base slant height)
11. LA = 4 (1/2 8
cm
7.5 cm)
         
           = 120 cm^2

12. LA = 4 (1/2
14 in
12in ) =

      LA = 336
cm^2


   Now
lets find the surface area:-

    surface area = lateral area + area of the base


   11. S.A. = 120 cm^2

  • 8 8

            
            = 120 cm^2 + 64

           
            = 184 cm^2

S.A. = 336 cm^2

  • 14 14

       
   12.     = 336 cm^2 + 196

       
             = 532 cm^2


Lateral
Area:-

11. 120 cm^2 
12. 
336 cm^2


 Surface
Area:-
11. 
184 cm^2
12. 532 cm^2

   
Hope
I helped ya!!