# Geometry: Angles and Triangles

Videos, worksheets, solutions and activities to help students learn about angles in Singapore Math.

Related Topics:
More Geometry Lessons
Singapore Math

In this lesson, we will learn

• what is an angle?
• what are angles on a straight line, angles at a point and vertically opposite angles?
• what is an isosceles triangle, an equilateral triangle and a right-angled triangle?
• what is the sum of angles in a triangle?
• how to draw different types of triangle?
• how to find unknown angles in a four-sided figure?
• how to draw a parallelogram, rhombus and trapezium?

Geometry - Introduction to angles
An explanation of what an angle is.

Geometry - Finding unknown angles
An explanation of

1. Sum of angles on a straight line
2. Sum of angles at a point
3. Vertically opposite angles.

Geometry - Different types of triangles
What is an isosceles triangle, an equilateral triangle and a right-angled triangle?

Geometry - Angle sum of a triangle
Why is the sum of angles of a triangle = 180 degrees?

Geometry - Drawing triangles using instruments - Example 1
Learn how to draw an equilateral triangle using geometrical instruments.

Geometry - Drawing triangles using instruments - Example 2
Learn how to draw an isosceles triangle using geometrical instruments.

Geometry - Drawing triangles using instruments - Example 3
Learn how to draw a triangle using geometrical instruments.

Geometry - Finding unknown angles in four-sided figures - Example 1
How do you find unknown angles in a four-sided figure?

Geometry - Finding unknown angles in four-sided figures - Example 2
How do you find unknown angles in a four-sided figure?

Geometry - Finding unknown angles in four-sided figures - Example 3
How do you find unknown angles in a four-sided figure?

Geometry - How to draw a parallelogram using instruments?

Geometry - How to draw a rhombus with instruments?

Geometry - How to draw trapezium with instruments?

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