A triangle is a 3-sided closed geometric figure and it belongs to the family of polygons. A triangle can be classified based on the sides and based on the angles of the triangle. Based on the sides, there is equilateral triangle, isosceles triangle and scalene triangle. Based on the angles, there is right angled triangle, obtuse triangle and acute triangle. In a triangle, various measurements such as side lengths, angles, areas etc. can be calculated using their respective formulas.
Example 1: Angles in a triangle are 55º, 75º and xº. What is the value of the third angle?
Sum of the angles in a triangle= 180º
This gives: 55º + 75º + xº = 180º
Now in order to solve for ‘x’, we can add the numbers first.
This implies: 130º + xº = 180º
Hence, xº = 180º - 130º = 50º
Therefore the measure of the third angle, x = 50º
Example 2: What is the area of a triangle whose base length is 12m and the height of the triangle is 15m?
Given: Base length of the triangle, b = 12m
Height of the triangle, h = 15m
Area of the triangle, A = 1/2 * base * height
This gives: Area of the triangle, A = 1/2 * 12m * 15m
So area of the triangle = 90m2
Therefore the area of the given triangle is 90 square meters.