Split it up into 4 separate shapes as shown in the attached picture:
shape 1 and 3 are identical triangles
area = 1/2 x B x H
area = 1/2 x 2 x 2 = 2 square cm each ( there are 2 so 2+2= 4 square cm for shape 1 & 3)
shape 2 is a rectangle area = L x w = 4*2 = 8 square cm
shape 4 is a triangle
area = 1/2 x b x h = 1/2 x 8 x 5.75 = 23 square cm
total area add all the shapes together: 4 + 8 + 23 = 35 square cm