Okkk so Surface area is the area of all the surfaces added together, this triangular prism consists of
2 triangles and 3 rectangles
To find the area of a triangle you do base x height divided by 2
To find the area of a rectangle
Length x width
Sooooo
Side 1= triangle
12x16/2: 96
Side 2= triangle
12x16/2: 96
Side 3= rectangle
12x10: 120
Side 4= rectangle
16x10: 160
Side 5= rectangle
10x20: 200
To find the SURFACE AREA
add them all together
96+96+120+160+200= 672 centimeters squared
Or square centimeters
SURFACE AREA UNITS is always squared so like square meters, centimeters, millimeters etc