If you work through this section you should be able to:
Angles are used to measure the amount by which a line has been turned. A full circle is 360 degrees.
Degrees and radians are the two commonly used units in measuring angles.
A circumference of a circle measures 2πr, so the number of radians in a full circle is 2π. Therefore:
There are five different types of triangle:
Equilateral Triangle (three equal sides) 

Isosceles Triangle (two equal sides) 

Right Triangle (with a right angle) 

Acute triangle (all angles less than 90°) 

Obtuse Triangle (one angle more than 90°) 
The three interior angles of a triangle always sum to 180°.
Area = $\frac{1}{2}$bh
Find the area of a triangle with a base of 10 metres and a height of 5 metres.
Area = $\frac{1}{2}$ × (10m) × (5m) = 25m^{2}
The area of a triangle shaped mat is 27 square metres and the base is 9 metres. Find the height.
27m^{2} = $\frac{1}{2}$ × (9m) × h
54m^{2} = (9m) × h
6m = h
Therefore, height is 6 metres.
You can download a version of this Triangles activity in Word format:
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