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Exploring Angles Concepts and Properties for Primary 5 & PSLE Math

Updated: Mar 21


Angles Concepts and Properties for Primary 5 & PSLE Math

The Primary School Leaving Examination (PSLE) in Mathematics covers a range of topics, including various properties of angles that are fundamental to understanding geometry. Here are some key angle properties and concepts that students preparing for the PSLE should be familiar with:


Types of Angles


Acute Angle


An angle less than 90 degrees is referred to as an acute angle. It's often visualised as a narrow angle, like the opening of a partially closed door.


Acute Angle

Types of Angles


Right Angle


An angle exactly equal to 90 degrees is termed a right angle. It's symbolised by a small square in the corner, and it represents a quarter turn.

Right Angle

Obtuse Angle


An angle greater than 90 degrees but less than 180 degrees is termed an obtuse angle. It's larger than a right angle but smaller than a straight angle.


Obtuse Angle

Tip: We can also use the corner of a ruler to check for right angles.


use the corner of a ruler to check for right angles

  • Angle B is a right-angle 

  • Angle C is bigger than a right angle 

  • Angle A is smaller than a right angle


Measuring Angles

Measuring Angles


To measure an angle, we utilise a protractor, a common geometry tool.When measuring angles with a protractor, the convention is to start from the initial side of the angle and measure either clockwise or counterclockwise depending on the angle's direction.


Properties of Angles

Properties of Angles


The sum of angles on a straight line is 180°


When two lines intersect, they form opposite angles on each side. These angles, when combined, form a straight line, and thus their sum is 180 degrees.


The sum of angles on a straight line is 180°

The sum of angles at a point is 360°


When multiple lines intersect at a single point, the angles formed around that point add up to 360 degrees. This property is fundamental in understanding the relationship between angles in geometric shapes.

The sum of angles at a point is 360°

Vertically Opposite Angles


When two straight lines cross, they form two pairs of vertically opposite angles. Vertically opposite angles are equal to each other. This property is crucial in solving various geometric problems involving intersecting lines.


Vertically Opposite Angles

understanding the concept of angles

In a nutshell, understanding the concept of angles and their properties is essential for Primary 5 & 6 students. From PSLE angle questions grasping the notion of vertically opposite angles and adjacent angles, a solid foundation in angle concepts sets the stage for tackling more complex geometric problems in higher grades. 


By comprehending how rays meet to form angles, recognising the significance of a common vertex, and appreciating the difference between acute and obtuse angles, students can confidently navigate through the world of geometry. So, let's encourage our young learners to explore angles with curiosity and enthusiasm, as angles are not just lines meeting at a common point but windows to understanding the intricacies of shapes and spaces.


Are you looking to give your child the edge in Primary Maths and ensure they excel in PSLE? Look no further than AGrader Learning Centre. Our Math Tuition Programme is specially designed to equip students with the skills and techniques needed to tackle challenging math problems with ease. With our proven methods, your child can solve 90% of difficult math problems quickly and efficiently. Our experienced Math tutors utilise heuristics to teach problem-solving skills, enabling your child to approach even the most complex problems with confidence and ease.


give your child the edge in Primary Maths

At AGrader, we are committed to ensuring that our students have a strong grasp of core Mathematical concepts. Through our Primary Math Programme, we not only teach these concepts but also train students to apply them effectively using critical thinking skills and heuristics. By doing so, we not only prepare our students for their school examinations but also instil in them a deep passion and appreciation for Mathematics. We believe in challenging our students to excel in the subject and pushing them to reach their full potential.


Don't let your child struggle with Math—enrol them in AGrader Learning Centre today and set them on the path to Mathematical success. 


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