What is a TRIANGLE?

An acute angle is any angle less than 90 degrees. So, as its name suggests, an acute triangle is a triangle whose three angles are all smaller than ninety degrees. So if all of a triangle's angles measure less than a right angle (a 90-degree, or square, angle), then it's an acute triangle.

Obtuse angles are simply angles larger than 90 degrees. We can spot them because they extend

past a right angle.

A right angle is an angle that measures exactly 90 degrees. It is exactly a quarter of a circle. When you cut a pie into four equal

pieces, the tip of each slice will form a right angle.

How to Classify Triangles

We can split the word 'equilateral' in two parts: 'equi' meaning equivalent and 'lateral' meaning side. So an equilateral

triangle is simply a triangle whose three sides are all equal.

An isosceles triangle is a triangle with two congruent, or equal, sides. For example, this is an isosceles

triangle:

Scalene triangles are triangles with three sides of different lengths. For example, a triangle with side lengths of 2 cm, 3 cm

and 4 cm would be a scalene triangle. A triangle with side lengths of 2 cm, 2 cm and 3 cm would not be scalene, since two

of the sides have the same length.

According to the classification of pages

Median and Angle Bisectors

Like any polygon, the perimeter is the total distance around the

outside, which can be found by adding together the length of each

side. Or as a formula :perimeter = a+b+c where:

a,b and c are the lengths of each side of the triangle In the figure

above, drag any orange dot to resize the triangle. From the side

lengths shown, calculate the perimeter and verify your result

matches the formula at the top of the diagram.

How to calculate the perimeter of a triangle

Usually called "half of base times height", the area of a triangle is given by the formula below. Area=ba/2.where b is the length of

the basea is the length of the corresponding altitude. The altitude is the line perpendicular to the selected base from the opposite vertex.

Area of a Triangle

Bermuda triangle