year 8 maths

Investigation
513
Exploring SSA
With the SAS test, the included angle must be between the two given sides. This investigation
will explore a triangle using SSA.
1 Construct a triangle with sides 5 cm and 3 cm and one angle 30° (not an included angle).
2 Can you construct a second triangle using the same information that is not congruent to the first?
3 Consider this diagram. Use it to help explain why SSA is not a test for congruence of two triangles.
30°
5 cm
3 cm
3 cm
Properties of quadrilaterals
1 Construct a parallelogram including its diagonals, as shown. Use the parallel line tool to create the
parallel sides.
D
C
A
E
B
2 Measure the sides and angles of △ABE and △CDE . What do you notice?
3 Now drag one of the vertices of the parallelogram. Does this change you conclusion from part b?
4 Explore other quadrilaterals by constructing their diagonals and looking for congruent triangles.
Write up a brief summary of your findings.
Cambridge Maths NSW
Stage 4 Year 8 Second edition
ISBN 978-1-108-46627-1 © Palmer et al. 2018
Cambridge University Press
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