# Problem Based on Triangle

Classification and properties of the triangle, we have discussed on the opening tutorial of this topic. Today, we are going to resume triangle mensuration formulas with all math tricks. Triangle math tricks are very important to the point of competitive math. We strongly recommend you to visit Triangle properties and classification for the clear concept.

## Perimeter area formula of triangle

Perimeter formula for Triangle: The perimeter is the outer length of any figure. So, it easy to find the perimeter of any triangle, when we know all the lengths of arms. Just, we have to add all arm's length. When we got equilateral triangle then we have to multiply an arm by 3. The formula became 3*an arm's length. When we will not get all arm's length then we have to follow the type of triangles or other formulae and then have to apply required formula or concept to find out the perimeter of a triangle. We hope, at the end of this tutorial, you will get it very well.

Triangle math tricks for area:

We know the above formula for calculating the area of the triangle. Where S represents the half of perimeter of the triangle and a, b and c are the lengths of three arms. This formula can be used to any triangle where we know the perimeter or able to find it. But sometimes, we can use some tricky shortcut formula to find the area of a triangle on some special triangles. Even we can simplify to find the area of a triangle by using some concept of triangles or merging with the quadrilateral figures.

#### Area formula for right angle triangle:  When we know a triangle is right angular and have to calculate it's area, then use the below formula.

How made the formula? This is a simple fact. Look at below, First one(pic 1) is a right angular triangle and the second one (pic2) is an imaginary figure of rectangular. As you know that the hypotenuse is the longest arm of a triangle as well as rectangular. If you imagine hypotenuse as a diagonal of a rectangular, the figure divides into two equal triangles. the formula of the rectangle is base*width Sq.units. So,  In this logic, you can say that the triangle is the half area of the rectangle. Also, note that all squares are rectangular.

Above formula, you can apply on any kind of triangle to calculate the area. Because you may have proved in geometry that when a triangle made with same base and height then the triangle will be half of the rectangular in point of the area.

#### Area formula of Equilateral Triangle: Shortcut area formula of an equilateral triangle is below.

In the next tutorial on the triangle, we will apply all formulas to a triangle mensuration problems.

Get the complete list of Area Formula of Circle, triangle, Quadrilateral Mensuration.