Total surface area of rectangular prism

Each side of a rectangular prism is called a face.

A rectangular prism has six faces.

In a rectangular prism there are 3 pairs of opposite and equal sides. The first pair is the red face

7 cm (l)

4 cm (b)

10 cm (h)

10 cm (h

7 cm (l)

We can see another face - just like the red face. That is on the back.

7 cm(l)

10 cm(h)

7 cm(l)

10 cm(h)

Now there are 2 rectangles that each have an area of 70cm² ie

lh+lh=2lh

l x h= 7 x 10= 70cm²

70 cm

2

70 cm

2

The second pair is the blue face

10 cm (h)

4 cm (b)

7 cm (l)

4 cm (b)

10 cm (h)

We can see another face - just like the blue face. That is on the left side.

10 cm (h)

4 cm (b)

4 cm (b)

10 cm (h)

Now there are 2 rectangles that each have an area of 40cm² ie

bh+bh=2bh

40cm²

40cm²

b x h= 4 x 10= 40cm²

The third pair is the green face

10 cm (h)

4 cm (b)

7 cm (l)

7 cm (l)

4 cm (b)

We can see another face - just like the green face. That is on the bottom.

4 cm (b) 4 cm (b)

7 cm (l) 7 cm (l)

Now there are 2 rectangles that each have an area of 28cm² ie

lb+lb=2lb

28cm²

28cm²

l x b= 7 x 4= 28cm²

Now we just need to add all the areas of the sides together.

+ +

+ + 28cm

2

40cm

2

70cm

2

70cm

2

40cm

2

28cm

2

The total surface area for this rectangular prism is