DIFFERENT TYPES OF TRIANGLES AND THERE DEFINATIONS
your spelling of equilatereal triangle is not correct
it is equilateral triangle
A triangle has three sides and three angles
The three angles always add to 180°
Equilateral, Isosceles and Scalene
There are three special names given to triangles that tell how many sides (or angles) are equal.
There can be 3, 2 or no equal sides/angles:
Three equal sides
Two equal sides
No equal sides
What Type of Angle?
Triangles can also have names that tell you what type of angle is inside:
All angles are less than 90°
Has a right angle (90°)
Has an angle more than 90°
Combining the NamesSometimes a triangle will have two names, for example:
Right Isosceles Triangle
Has a right angle (90°), and also two equal angles
Play With It ...
Try dragging the points around and make different triangles:
You might also like to play with the Interactive Triangle.
The perimeter is the distance around the edge of the triangle: just add up the three sides:
The area is half of the base times height.
- "b" is the distance along the base
- "h" is the height (measured at right angles to the base)
Area = ½ × b × h
The formula works for all triangles.
Note: a simpler way of writing the formula is bh/2
Example: What is the area of this triangle?
(Note: 12 is the height, not the length of the left-hand side)
Height = h = 12
Base = b = 20
Area = ½ × b × h = ½ × 20 × 12 = 120
The base can be any side, Just be sure the "height" is measured at right angles to the "base":
(Note: You can also calculate the area from the lengths of all three sides using Heron's Formula.)
Why is the Area "Half of bh"?
THEN the whole area is bh, which is for both triangles, so just one is ½ × bh.
Scalene triangle - A triangle which does not has any of its side equal.
Iscosceles triangle - A triangle which has only two of its sides equal.
Equilateral triangle - A triangle that has all its sides equal is known as an equilateral triangle.
1.Triangles based on sides
i)Equilateral triangle-All sides are equal.
ii)Isosceles triangle-Any two sides are equal.
iii)Scalene triangle-All sides are of different length.
2.Triangles based on angles
i)Acute angled triangle-All angles are less than 90degrees.
ii)Right angled triangle-One angle measures 90degrees.
iii)Obtuse angled triangle- One angle measure more than 90degrees.