Surface Area

1
Surface Area

• 3D shapes

2
The Final Week...

• Today and tomorrow (Mon/Tues) will be dedicated
  to finishing surface area and volume.
• Wed-Fri will be review days (Finance,
  Geometry/Trig and Measurement).
• Our exam is WEDNESDAY, JANUARY 25TH, FROM
  845AM-1045AM IN THE GYM.

3
Instructions for use

• There are 9 worked examples shown in this
  PowerPoint
• A red dot will appear top right of screen to
  proceed to the next slide.
• Click the navigation bar to the left of screen to
  access relevant slides.

4
3 easy steps to calculate the Surface Area of a
solid figure

1. Determine the number of surfaces and the shape
   of the surfaces of the solid
2. Apply the relevant formula for the area of each
   surface
3. Sum the areas of each surface

5
Surface Area Basic concept
rectangle
rectangle
rectangle
square
square
rectangle
Determine the number and shape of the surfaces
that make up the solid.
When youve done all that find the area of each
face and then find the total of the areas.
It might be easier to think of the net of the
solid.
6
Square prism
Find the surface area of this figure with square
base 5 cm and ? height 18 cm
Two square faces
Four rectangular faces
18 cm
5 cm
7
Rectangular prism
Find the surface area of this figure with length
10 cm, width 15 cm and height 12 cm.
20 cm
15 cm
5 cm
8
Triangular Prism
Find the surface area of this figure with
dimensions as marked.
9
Square Pyramid
Find the surface area of this figure with square
base 10 cm and ? height 12 cm.
4 triangular faces with the same dimensions and 1
square face
We need to find the ? height of each triangular
face.
12
10
Rectangular Pyramid
Find the surface area of this figure with
dimensions as marked.

• 5 faces altogether
• 2 pairs of congruent triangular faces
• 1 rectangular face

First find the unknown heights using Pythagoras
theorem
11
Cylinder
Find the surface area of this cylinder with
height 25 cm and diameter 20 cm.
Think of the net of the cylinder to understand
the formula.
12
Cone
Find the surface area of this cone of height 15
cm radius 5 cm.
13
Sphere
Find the surface area of this sphere with
diameter 5 cm.
Required formula
Easy! The sphere is one continuous surface so
just substitute into the formula
14
Hemisphere
Find the surface area of this hemisphere with
diameter 5 cm.
A hemisphere is a half sphere. But we need
to add in the area of the circular base.
Required formula
15
Last slide
Use the navigation buttons to repeat selected
slides.