Question

Find the surface area of the composite figure.

4 cm
5 cm
3 cm
3 cm
4 cm
21
6 cm
5 cm
4 cm

Answer 1

132cm²

Explanation:

Split into two shape: Cube & Triangle prism

Cube surface area:

1) area of top & bottom

(4×3)×2= 12×2= 24cm²

2) area of the sides (only three sides as for surface)

(3×6)×3= 18×3= 54cm²

Triangle prism surface area:

1) area of two sides of triangle:

(½×6×4)×2= (3×4)×2= 12×2= 24cm²

2) area of two sides of rectangle:

(5×3)×2= 15×2= 30cm2

Total surface area: 24+54+24+30= 132cm²