help me FAST!!!

 

   what is the lateral surface area of a trianglular pyramid in which the base is an     

   equilateral triangle with a side of 12 inched long and a slant height of 20 inches     

 

 

   When you say lateral surface area, that means just the sides, excluding the base.     

 

 

   Area_side  =  (1/2) • base • height     

   Area_total  =  (1/2) • base • height • 3     

 

     Total Area  =  (1/2) • 12 in • 20 in • 3     

                       =  (1/2) • 240 in² • 3     

                       =  120 in² • 3     

                       =  360 in²     

   _.