Exam Questions on Types of Triangles
You will need to know the different types of triangles for your entrance exam.
Your should also understand some basic rules about the types of triangles.
Types of Triangles – Definitions
Isosceles
An isosceles triangle has two equal sides and two equal angles.
An example of an isosceles triangle is shown below:
Equilateral
An equilateral triangle has three equal sides and three equal angles.
The illustration below shows an equilateral triangle:
Congruent
Equilateral triangles are sometimes called congruent triangles.
That is because angles that have the same measurement in degrees are called congruent angles.
Obtuse
An obtuse triangle has one angle that is greater than 90 degrees.
So, an obtuse triangle can look something like the following illustration:
30 – 60 – 90 Triangle
The sum of all three angles in any triangle must be equal to 180 degrees.
This is true in a 30 – 60 – 90 triangle because 30 + 60 + 90 = 180.
The sides of a 30° – 60° – 90° triangle are in the following ratio: 1: √3 : 2
45 – 45 – 90 Triangle
Remember that the sum of all three angles in any triangle must be equal to 180 degrees, so in this type of triangle: 45 + 45 + 90 = 180
You may also want to see our posts on the the area of a triangle and the area of a square.