Here are a few important facts we need to know for our work with triangles!
A right angle is 90º
An acute angle is less than 90º
An obtuse angle is between 90º and 180º
A straight line angle is 180º
A reflex angle is between 180º and 360º
A right-angled triangle has one 90º angle.
An isosceles triangle has two equal angles.
An equilateral triangle has three equal angles, each of size 60º.
A scalene triangle has three different angles.
That's a lot to remember, but it's all very important stuff to know and will really help you in your geometry work!
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Let's get practising!