Angles in shapes for AQA GCSE Maths
This page covers the following topics:
1. Sum of angles in a triangle
2. Sum of angles in a square
3. Sum of angles and inner angles
4. Sum of angles and outer angles
The sum of interior angles in a triangle is 180°. If the side of a triangle is extended, an angle is created outside the triangle called an exterior angle.
A square has 4 interior angles, all of equal size 90°.
The sum of interior angles in a polygon can be found by dividing the polygon into a number of triangles.
The exterior angles of a polygon can be found by extending the sides of the polygon to form an angle outside the shape.
Calculate the sum of interior angles in a pentagon.
Calculate the size of the exterior angles in the shape shown and hence, calculate the size of the interior angles.
exterior angle = 72°
interior angle = 108°
If x is the number of sides in a polygon, write a formula that can be used to find the sum of interior angles in the polygon.
180º(x − 2)
Find the size of angle x.
Calculate the sum of the interior angles in the shape shown.
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