Starter QuestionsStarter QuestionsWednesday 18th August

1. Calculate the circumference of a circle with the following diameters

a) 20cm b) 12cm c) 8cm

2. Calculate the area of this shape

4m

Faces Edges and VerticesFaces Edges and Vertices

Learning IntentionLearning Intention

To understand the meaning of Face Edge and Vertex in relation to various shapes an be able to identify them.

To draw the net of a cuboid and work out its surface area.

33

Revision of AreaRevision of Area

2Area l l l 12

Area b h

l

l

Area l b

l

b h

b

The Square The Rectangle The RAT

Face Edges and Vertices

The shape below is called a cuboid.

It is made up of FACES, EDGES and VERTICES.

Faces are the sides of a shape(surface area)

Edges are where the two

faces meet (lines)

Vertices where lines meet (corners)

Don’t forget the faces edges and corners we can’t see at the back

Face Edges and Vertices

Front and back are the same

Top and bottom are the same

Right and left are the same

Calculate the number of faces

edges and vertices for a cuboid.

6 faces

12 edges

8 vertices

Face Edges and Vertices

Faces are squares

Calculate the number of faces

edges and vertices for a cube.

6 faces

12 edges

8 vertices

Front Area = l x b= 5 x 4 =20cm

2

Example Find the surface

area of the cuboid

Working

5cm

4cm

3cm

Top Area = l x b

= 5 x 3 =15cm2

Side Area = l x b

= 3 x 4 =12cm2

Total Area

= 20+20+15+15+12+12= 94cm

2

Front and back are the same

Top and bottom are the same

Right and left are the same

= 2 x3 =6cm2

Example Find the surface area of the right

angle prism

Working

Rectangle 1 Area = l x b

= 3 x10 =30cm2

Rectangle 2 Area = l x b

= 4 x 10 =40cm2

Total Area = 6+6+30+40+50 = 132cm

2

2 triangles the same

1 rectangle 3cm by 10cm

1 rectangle 4cm by 10cm

3cm

4cm

10cm

1 rectangle 5cm by 10cm

Triangle Area =1

bh2

Rectangle 3 Area = l x b= 5 x 10 =50cm

2

5cm

Face Edges and Vertices

Calculate the number of faces,

edges and vertices for these shapes

Cylinder

Cone

Sphere

Triangular Prism

3 faces2 edges

0 Vertices

5 faces9 edges

6 Vertices 2 faces1 edges

1 Vertices

1 faces0 edges

0 Vertices

BottomTopleftSideBackRightSideFront

The net of a solid shape is the shape you would getThe net of a solid shape is the shape you would getif it was made of cardboard and you “opened it upif it was made of cardboard and you “opened it upand laid it out flat”. and laid it out flat”.

This is a NET for the cube

Net and Surface Area Net and Surface Area The CubeThe Cube

6 facesAll congruent

Question : Find the surface area of the cube below.

Net and Surface Area Net and Surface Area The CubeThe Cube

5cm

What do we know?

• Made up of 6 facesMade up of 6 faces

• All the same (congruent)All the same (congruent)

• All squaresAll squares

Area = length x length

= l x l

2

= 5 x 5

= 25 cm

Total6 x 25 = 150cm

2

Bottom

Top

LS Back RS

Front

This is a NET for the cuboid

Net and Surface Area Net and Surface Area The CuboidThe Cuboid

6 faces

Top and bottom congruent

Front and back congruent

Left and right congruent

5cm

4cm

3cm

5cm

3cm

4cm

3cm

4cm

Front Area = l x b= 5 x 4 =20cm

2

Example Find the surface

area of the cuboid

Working

5cm

4cm

3cm

Top Area = l x b

= 5 x 3 =15cm2

Side Area = l x b

= 3 x 4 =12cm2

Total Area

= 20+20+15+15+12+12= 94cm

2

Front and back are the same

Top and bottom are the same

Right and left are the same

Now try Ex 4.1Ch2 (page 27)

Net and Surface Area Net and Surface Area The CuboidThe Cuboid