Answer:
45
Step-by-step explanation:
the formula is (P x slant height over 2) + B
P = perimeter of the base
B = area of the base
P = 3+3+3+3 P=12
B=3x3 B = 9
12 x 6 = 72 72 divided by 2 = 36 36 + 9 = 45
the surface area of your triangle is 45 cm squared
