$K6 Math Logo$

$return to homepage$

$K6 Math Logo$

Home

Math Videos

Blog

E-Zine

Contact Me

E-Store

Site Search

The Isosceles Triangle - What Must be known by your K6 Student

The term Isosceles triangle is the second of six means of identifying triangles that we are covering in the triangle section of our Master Basic Geometry journey.

This shape is important in the future study of the circle, because of its characteristic of having two sides the same length.

$isosceles triangle$ In this diagram, a = b. Be sure to direct your child’s attention to the double line symbol under a and b. This is a standard method of indicating lines that are the same length in polygons. Also, the base angles are indicated using the same symbol (any symbol can be used), as they are also equal.

The area of an Triangle which is Isosceles is calculated in the same manner as ANY triangle. This is covered in our Right Triangle section.

So What is and Isosceles Triangle?

It is a triangle that:

ALWAYS has two sides the same length.

Both its base angles are ALWAYS the same size

Your child must know the Isosceles Triangle Theorem that proves these statements.

Can an Isosceles Triangle be Right, Acute or Obtuse?

Yes, it can actually be any one of these.

If it has one Right Triangle it becomes a Right Isosceles Triangle .

If it has One angle Greater than 90 degrees it becomes an Obtuse Isosceles Triangle.

If ALL Three of its angles are less than 90 degrees it becomes an Acute Isosceles Triangle.

What else is important to know.

Because we know the sum of all angles in any triangle is 180 degrees, this tells us that the third angle is 180 degrees – two times the base angle.

Knowing just one angle allows us to find the remaining two with ease.

If you place your compass at the vertex not at the base angles, and draw a circle, with a radius length of one of its sides, you will see that the two vertices at the base angles will be on the circle. This is because the two sides that are the same length are the radii of the circle.

If you found this information helpful, you might enjoy touring our other Geometry sections.

Having helped your child learn this information, reinforcing it through practice is essential, to help them remember it.

For other areas of K6 Math use the navigation bar on this page to take you directly there!

Don't miss this oportunity to subscribe to my e-zine

Elementary Math Fun

This is a bi-monthly publication which will give you suggestions on how to make math entertaining and fun for your child!