Hello!
To find the surface area you can divide the prism into the 2D shapes it is made of
First list out all the shapes
2 triangles with bases of 18 and heights of 15.6
3 rectangles with side lengths of 20 and 18
First find the area of the triangles
The equation to find the area of a triangle is
[tex]A = \frac{hb}{2} [/tex]
A is area
h is height
b is base
Put in the values you know
[tex]A = \frac{18 * 15.6}{2} [/tex]
Solve
A = 140.4
The triangles have an area of 140.4 units
Next we find the area of a the rectangles
To do this we multiply the sides
18 * 20 = 360
The rectangles have areas of 360 units
Now we add all the areas
There are 2 triangles and 3 rectangles
140.4 + 140.4 + 360 + 360 + 360 = 1360.8
The answer is B) 1360.8cm squared
Hope this helps!
