Explanation:
the total surface area is the sum of the individual areas on the surface.
we have
2 triangles (top and bottom)
1 front rectangle
2 rectangles in the back
the area of a triangle is
baseline × height / 2
1.7 × 0.5 / 2 = 0.425 in²
both triangles together : 2×0.425 = 0.85 in²
the area of a rectangle is
length × width
so, the front is
1.7 × 1.5 = 2.55 in²
one back rectangle is
1 × 1.5 = 1.5 in²
both back areas are 2×1.5 = 3 in²
so, the total surface area is
0.85 + 2.55 + 3 = 6.4 in²