What is Triangle?
A triangle is a three-sided polygon that has three vertices, or corners. Triangles are commonly used in construction to create supporting structures and figure heavily in artworks.
Area using Base and Height
Area of triangle = 1/2 x base x height
Area using lengths of 3 sides
Lets take a, b and c are lengths of 3 sides of a triangle.
Area of triangle = 0.25 * √( (a + b + c) * (-a + b + c) * (a - b
+ c) * (a + b - c) )
Area using Two sides and the angle between them
Lets take a, b are lengths of 2 sides of a triangle and γ as angle between them.
Area of triangle = 0.5 * a * b * sin(γ)
Types of triangle - Angles
- A triangle having a right angle(90°) is called a right angled triangle.
- A triangle with all angles measuring less than 90° is called an acute angled triangle.
- A triangle with an angle measuring more than 90° is called an obtuse angled angle.
Types of triangle - Sides
- A triangle is considered to be an equilateral triangle when all three sides have the same length.
- When two sides of a triangle are equal or congruent, then it is called an isosceles triangle.
- When none of the sides of a triangle are equal, it is called a scalene triangle.
Other facts about triangle
- The three internal angles of a triangle always add to 180 degrees.
- The longest side of a right angle triangle is called the hypotenuse, it is always found opposite the right angle.
- Sum of two sides of a triangle is always greater than the third side.