Transcript Constructing Triangles

Estimate
Now
measure
the angle?
the angle?
150º
Estimate
Now
measure
the angle?
the angle?
215º
Constructing triangles
Aim: To construct triangles using a protractor.
60º
Draw a triangle with one side 6cm and angles at each end of 30º and 70º.
Mark 70º
Mark 30º
6 cm
Draw a triangle with a side 12 cm and side 9 cm
with an angle of 75º between them.
Mark 75º
12 cm
Three ways to construct triangles.
When constructing triangle we need a combination of angles of lengths.
 We can construct triangles with a compass if we have the lengths of
the 3 sides (S S S).
 We can construct triangle using a protractor if we have the length of
1 side and the measurement of 2 angles ( A S A ).
 We can construct triangle using a protractor if we have the length of
2 sides and the measurement of 1 angles ( S A S ).
Note:
To construct triangles, we need to know the length of at least 1
side plus 2 other pieces of information.
Task and Homework
Construct the following triangle:
S S S Triangles
A S A Triangles
A S A Triangles
5cm
7cm
9cm
40º
7cm
50º
7cm
50º
4 cm
6cm
6 cm
4cm
45º
6 cm
45º
6 cm
45º
6 cm
10cm
8cm
7cm
20º
8cm
100º
8cm
100º
6 cm
6cm
8cm
10cm
60º
8cm
60º
8cm
60º
8 cm
7cm
7 cm
7 cm
110º
7 cm
45º
7 cm
45º
6 cm