336
Explanation:
I'm learning the same thing. Multiply the base, 12 x 12 = 144. Multiply each other lateral faces (the triangles) 1/2 bh = 1/2 12 x 8 = 6 x 8 = 48. Then multiply that by 4 or add it 4 times since there is 4 sides. 48 x 4 = 192 or 48+48+48+48 = 192. Then add 192 and 144. 192 + 144 = 336 so they surface area of this is 336. let me know if you need more help :)