Surface area of composite solids 1
Surface
Lesson overview
Outcomes
Students use Google SketchUp to model 3D shapes and begin to calculate
the surface area of composite solids by rotating them and using the
dimensions tool.
Stage 5
Software used
Stage 6 General Mathematics
Google SketchUp
M5 Further applications of area and
volume (H6)
MS5.2.2 Calculates the surface area
and volume of composite solids.
Activity
How to ... step-by-step
Open a new Google SketchUp page.
This is the model students recreate:
1. Recreate the model using Google
SketchUp.
(diagram not to scale)
19
10
to split any
2. Use the Line tool
composite shapes into simpler shapes.
3. Use the Dimensions tool
to show any
dimensions that would be helpful to
calculate the area of each face.
4. Calculate the area of each face (or section
of a face) and record the area.
8
25
32
Select the rectangle tool
. Click once to start
the rectangle and once to stop it.
5. Use the Paint Bucket tool
to colour
each face (or section of a face) as it is
calculated.
6. Use the Orbit tool
to change the point
of view to make sure each surface area has
been calculated.
7. Take a screen clip of the model created.
Paste the clip, the areas of each surface
and the total surface area into a OneNote or
Word file.
Note: A completed Google SketchUp file of this
activity, Surface area of composite solids 1, is
available for download.
© Commonwealth of Australia 2009
Type the dimensions of the rectangle (there is no
need to click anywhere) as ‘32m, 25m‘press Enter.
Typing will appear in a box at the bottom of the
screen.
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Zoom in or out by using the scroll wheel on the
mouse or the Zoom button.
(Click anywhere
and move towards the bottom of the screen to
zoom out or towards the top of the screen to zoom
in.)
Use the Pan tool
Pull up this rectangle using the Push/Pull tool
(click on the surface and drag up). Type the
dimension ‘10m’, press, Enter.
to get the image to a
desired part of the screen.
Use the Push/Pull tool
to add a third
dimension to the shape. Select the tool, click on
the rectangular surface and drag upwards. Enter
the height by typing 8m, Enter. There is no need to
click anywhere.
Add any extra lines to your diagram that might be
needed to split composite shapes into simpler
shapes. Select the Line tool
, click once
where the line starts and once where the line stops.
Draw another rectangle on the top surface of the
prism using the Rectangle tool
dimensions “25m, 19m”, “Enter”.
. Type in the
Orbit the figure by selecting the Orbit tool
,
clicking anywhere on the page and dragging the
mouse around. Find any other sides that need
extra lines and add them in remembering to check
underneath the figure.
© Commonwealth of Australia 2009
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Add measurements to your diagram. Select
dimensions from the Tools menu.
As each area is calculated, use the Paint Bucket
to colour the area. This technique
tool
ensures no surfaces are
missed.
Choose a material from the
list.
E.g. Colours , select a colour
Click once on the side to be measured and move
the mouse out from the side.
Click once on the surface to be coloured.
Click on each edge to show the dimension, and
move the mouse away to place each
measurement.
Each surface can be colour coded with a different
colour or texture if required.
Add as many dimensions as is needed. What is the
minimum number of measurements needed on this
shape in order to calculate the surface area?
Students calculate the area of each face (or section
of a face) and record their results.
© Commonwealth of Australia 2009
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