Angles and Triangles
Year 4 learn angle types and the properties of triangles.
# Angles and Triangles
In Year 4 geometry we learn about angles and the special properties of triangles.
Types of Angle
An angle is made where two lines meet. A right angle is 90 degrees, like the corner of a square. An acute angle is smaller than 90 degrees. An obtuse angle is bigger than 90 degrees but smaller than 180 degrees.
Angles in a Triangle
The three angles inside any triangle always add up to 180 degrees. If you know two angles, you can work out the third by subtracting from 180.
Types of Triangle
An equilateral triangle has three equal sides and three equal angles of 60 degrees. An isosceles triangle has two equal sides and two equal angles. A scalene triangle has no equal sides or angles. A right angled triangle has one 90 degree angle.
Try It
Draw a triangle and label its angles. Add them up to check they total 180 degrees. This check helps you catch mistakes when working out missing angles.
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