Properties of Shape - Angles in a Triangle (1) - Worksheet

The "Angles in a Triangle (1)" worksheet is a comprehensive resource designed to help Year 6 students understand the properties of different types of triangles and how to calculate their interior angles. The National Curriculum objective is to compare and classify geometric shapes, such as equilateral, isosceles, scalene, and right-angled triangles, based on their properties and sizes. Students will also learn to find unknown angles in triangles, quadrilaterals, and regular polygons. For this lesson, they will need differentiated sheets and teaching slides, and they will be introduced to key vocabulary such as angle, interior angles, and specific triangle types.

The worksheet encourages hands-on exploration, with students using coloured card to create triangles and a protractor to measure angles. They will discover that the sum of the interior angles of a triangle always adds up to 180 degrees. This knowledge is applied to find missing angles, regardless of the triangle's type or size. Key questions prompt students to consider the similarities and differences between triangle types and to verify that the triangle's size does not affect the sum of its interior angles. The worksheet also includes reasoning and problem-solving challenges, where students must evaluate statements about triangles and demonstrate their understanding by working out specific angle sizes, further reinforcing the concept that a triangle can never have three obtuse or three right angles.