Master the Scalene Triangle
From Recognition to Construction

The Scalene Triangle, like the equilateral triangle and the isosceles triangle is identified by its line lengths.

A Scalene triangle will ALWAYS have NO sides equal in length.  As with this stage of geometry your child should easily be able to distinguish whether two lines are equal in length or not.  If they can't, you need to take them back to develop this skill.

5 Stages to master any shape

The five steps detailed bellow take you from basic identification all the way through to taking a detailed look at the theorems involving the isosceles triangle.

These steps also include 'pit stops' to complete fun geometry projects and coloring sheets. These are nice 'breathers' on the learning curve, but they are excellent ways of reinforcing the new knowledge in ways that your kid can get a real life, hands on approach to understanding the basic geometry concepts included.

Okay, so let's get started ...

Stage 1 - Identify

How do we know what we look at is an Isosceles Triangle?

First and fore most a Isosceles triangle is a polygon (many sided shape) with three sides (a triangle) .

  1. It has 3 sides.
  2. It is a closed shape.
  3. None of the sides are the same length.

If no sides are equal in length, then no two angles are equal in size either.  

In a math question, the given information may indicate either side lengths or angle size for a triangle.

In either case students have to identify the triangle as scalene.

A scalene triangle, can also be a Right triangle.  

This is called a Right scalene Triangle.

Once your child is comfortable with how to recognize the trapezoid, offer them some shape worksheets to see how they get on with identifying the shape when compared with others.

You may also find our  Quadrilateral Family Tree Printable a useful tool to offer your child.

Calculate Area and Perimeter


The Area  of a this type of triangle is calculated the same way as EVERY triangle. It is always,

half the length of the base multiplied by the perpendicular height

of the triangle, in this case, the perpendicular height is always the length of the vertical side of the triangle.


The Perimeter of ANY shape is simply the sum total of all the lengths of the shape - and a triangle is no different.

The perimeter of a triangle is the sum of its lengths. 

How to construct a Trapezoid

To complete this, you will need a ruler, pencil, compass, and a blank piece of paper!

Constructing a scalene triangle at the elementary level is actually quite simple.

Just draw three lines, ensuring none are of the same length, and you have it!

Download triangle worksheets,  to offer your student the practice they need to identify these shapes.

Relationship to 3D-Shapes

The 3d Figures a Kindergarten through sixth grade student is most likely to deal with, created by this triangle will  be a Triangular Prism and all the different pyramids.

Geometric Coloring

The use of coloring sheets allows your child to start experimenting with different shapes.  A great first step is to encourage your child to color in shapes adjacent to each other with the same color, until their shape starts to look like 'something'.

Perhaps that something will be a rectangle or a house.  By doing this, your child will start to realize the connection between the shapes.  

You will find some nice free geometric coloring pages to download here.

Head from the Scalene Triangle to explore all the other triangles on the elementary mathematics curriculum.

Enjoy this page? Please pay it forward. Here's how...

Would you prefer to share this page with others by linking to it?

  1. Click on the HTML link code below.
  2. Copy and paste it, adding a note of your own, into your blog, a Web page, forums, a blog comment, your Facebook account, or anywhere that someone would find this page valuable.

I am sure you will find all the information and worksheets you need here, however if there is anything you cannot find please don't hesitate to contact me or simply visit the MathMomentumCommunity and join the conversation!

I love to hear from my readers, and with a little feedback and a few suggestions I can make this a great resource for parents, teachers and tutors alike.

Be sure to explore everything on this site starting at the home page.