Did you know your child will come across four different types of triangles throughout Primary 6 and 7? These different types of triangles can easily make your child’s head spin! And yours! Triangles sound like a really easy maths topic. But of course, triangles in maths aren’t just recognising the pointy shape. There are lots of other mathematical bits and bobs that go along with it! So in this week’s blog post, I am going to go through the various types of triangles that your child needs to learn about. I’ll also show you how they can make an appearance in the SEAG transfer test!
Speaking of the transfer test, if your child is preparing for their transfer test, you can download a FREE 30-minute practice paper here! This 30-minute paper is perfect for revision or practising test technique. Once you download your FREE paper, you’ll be signed up to my email list where you will get lots of weekly English, Maths and transfer test tips and tricks!
What are triangles?
Before we get started on the types of triangles with properties that your child needs to learn about, there are a few basic triangle facts that you need to know first! What are triangles? Triangles are 2D shapes which have three sides and three corners. 2D shapes are two-dimensional shapes. This means that they are flat compared to 3D shapes such as a cube or cylinder, which you can hold in your hand.
Angles in a triangle
Each shape has different angles inside, which all add up to different amounts. All triangles have three angles, and all three angles must add up to 180° in total. This is the first key fact that your child needs to know about triangles. There is 180° in a triangle. Write this on a Post-It note or stick it on the fridge. This is something that your child needs to remember when working with triangles, especially during transfer test preparation.
What are the different types of triangles in maths?
It would be so easy if there were just your bog standard triangle and that was it. But of course that’s not the case! There are four types of these three-sided shapes that your child will learn about throughout Key Stage 2. They are the equilateral triangle, isosceles triangle, scalene triangle and right angle triangle. I’m going to go through each of these triangles one by one.
Equilateral Triangle
The first triangle on our list is the equilateral triangle. This is the basic triangle that your child will start learning about from those early days of learning about shapes. The clue is in the name with this one. Equilateral triangles have sides that are all equal in length, and all of the angles in the triangle are equal. There are 180° in a triangle, and to find the value of each of the angles in an equilateral triangle, we divide 180 by 3. This gives us 60, which means each of the angles in an equilateral triangle is worth 60°.
Isosceles Triangle
The second triangle on our list is isosceles. This can be an absolute nightmare to remember how to spell! This is usually shown as a tall, skinny triangle. However, it can be short and wide as well. The main properties of an isosceles triangle are that two sides are the same length and two angles in the triangle are also the same. When it comes to angles in an isosceles triangle, it’s the two lower angles that are the same. Sometimes this will be shown on the triangle as two diagonal lines on each side of the triangle.
Scalene Triangle
The third triangle that your child will be learning about is the scalene triangle. This is the one that can look a bit crazy at times. The reason for that is that each side in a scalene triangle is a different length. Each angle in the scalene triangle is different as well. Sometimes a triangle will be subtly scalene, meaning each of the sides is only slightly different, and these can be trickier to spot. Other times, each side is very clearly different, and this is when a scalene triangle can look a bit crazy! As long as each of the angles in the triangle is different and adds up to 180°, this means that the triangle is scalene.
Right Angle Triangle
This is probably one of the easiest of the triangles to recognise because a right-angle triangle has a very distinguished shape. It’s got two completely straight sides, like an L shape, and there is a right angle in the corner. That’s why it’s called a right-angle triangle, a very original name! There is 90° in a right angle so with the right angle triangle one of the angles must be 90°.
Types of Triangles Transfer Test Questions
The various types of triangles can come up in a variety of ways in the SEAG transfer test. The most important thing, first off, is that your child can identify the different types of triangles and understand the different properties of each triangle. This knowledge will help them answer the transfer test-style questions based on triangles. The triangle questions that I have seen come up in the transfer test in the past are:
- Recognising the different triangles
- Missing Angles in a Triangle
- Types of Angles in a Triangle
- Area of a Triangle
- Word Problems
Let’s go through a SEAG transfer test style of triangle questions for each of these ways, so you know what to expect during your child’s transfer test preparation.
Recognising the different triangles
The first type of triangle question that can make an appearance in the transfer test is asking which triangle is shown. I think this is the easiest type of triangle question that students can be asked. This is when a picture of a triangle is shown, and the question is simply which shape or which type of triangle is shown below.
Missing angles in a triangle
This is when your child’s knowledge of the triangle properties comes into play! They will be required to find the missing angles in a triangle. With these types of questions, your child will have to recognise which type of triangle is in the question, remember how many degrees are in a triangle in total and then do some adding and subtracting! For example, what is the value of the missing angle from the triangle below?
Types of angles in a triangle
This type of triangle transfer test question requires your child to know the different types of angles. The types of angles that can be in a triangle are acute, right and obtuse. An acute angle is less than 90°, a right angle is 90°, and an obtuse angle is more than 90° and less than 180°. There can’t be any reflex angles in a triangle because reflex angles are more than 180°, and there is only 180° in a triangle. If you would like more info on the different types of angles, check out my blog post, ‘How to help your child ace their types of angles maths homework’ here!
An example of a transfer test style types of angles in a triangle would be: What type of angle is the missing angle from the isosceles triangle below?
Area of a Triangle
This type of question is an area and triangle question combined! Finding the area of a triangle is different from finding the area of a square or rectangle, for example. There are two ways to find the area of a triangle, you can try both of these ways and see which works best for your child. Option 1 is to halve the base of the triangle and multiply it by the height of the triangle. Option 2 is to multiply the base of the triangle by the height of the triangle, and then half your answer.
A transfer test style area of a triangle question could be: What is the area of the shaded triangle below?
Word Problems with Triangles
You might not think that you could get a word problem involving triangles, but you can! It will more than likely be combined with an area or perimeter question. However, a knowledge of triangles is essential for this. For example, Alan is setting up a gazebo for his daughter’s birthday party. He draws a plan of the size of the gazebo that he needs. What is the area of the gazebo that Steve needs for his party?
How to teach your child about triangles
If your child struggles with the different types of triangles, there are a few things that you can do to help with their learning and understanding. Sometimes, when my students see a particular type of question in a worksheet format or in a transfer test practice paper, they panic and think they can’t do it! But sometimes changing up the context and format can help build their skills and confidence with different topics. Let me share some of my ideas, which you can use at home to help teach your child about triangles!
Get out and about
There are triangles all around us in our everyday lives. We don’t notice them! Go out for a walk and try to spot some triangles outdoors. When you spot one, ask your child to tell you which type of triangle it is: right, equilateral, isosceles or scalene! Some roofs of houses or sheds are triangular-shaped, or patterns on clothing. Even a bag of Doritos is a full bag of triangles! Well, apart from the crushed ones!
Whose turn is it?
Just like with every maths topic, the best way to learn and reinforce a concept is by having some fun with it! That’s right, it’s game time! There are lots of types of triangle online games where players have to work with different triangles and angles. Triangles and angles splat is a super fun online game. Some others are Area of Triangles Game Show, Classify Triangles Whack-A-Mole and Triangles Quiz! All of these games are free and can help your child develop their knowledge of triangles! There are lots of great printable triangle games, and you can even make your own as well!
Get creative
A way to get this new triangle knowledge to ‘sink in’ is to create a types of triangles poster or a types of triangle chart. Grab some cards, coloured pens and get your child to create their own posters, charts and revision cards. You can also use some wooden sticks to create the different types of triangles.
Let’s put pen to paper
Once your child has played lots of fun triangle games, created their posters and spotted lots of triangles in their everyday lives, it’s time to put pen to paper. Worksheets are a great way to solidify your child’s new triangle skills! You can get some free triangle worksheets here to get you started!
More information on the different types of triangles
How to Teach Your Child About the Types of Triangles with Easy Examples
Teaching the Types of Triangles with Math Wheel Magic!
If your child gets jumbled or confused with the different triangle topics, keep practising and going over each section until they are confident with it. The more they learn and practice working with triangles, the easier it’ll be to recall the properties of the different triangles. I hope this has helped you and your child understand everything they need to know about the different types of triangles!
