Explanation:
A triangle is one of the basic shapes of geometry: a polygon with three corners or vertices and three sides or edges which are line segments. A triangle with
vertices A, B, and C is denoted ABC.
In an isosceles triangle, two sides are equal in
length. An isosceles triangle also
has two angles of the same measure (Our solved
example in mathguru.com uses this concept);
namely, the angles opposite to the two sides of the same length; this fact is
the content of the Isosceles triangle theorem. Some mathematicians define
an isosceles triangle to have exactly two equal sides, whereas others define an
isosceles triangle as one with at least two equal sides. The latter definition would make all
equilateral triangles isosceles triangles.
Computing
the area of a triangle
The
area of a triangle can be demonstrated as half of the area of a paralellogram which has the same base length and
height.
Calculating the area of a triangle is an elementary problem
encountered often in many different situations. The best known and simplest
formula is:
where b is the length of the base of the
triangle, and h is the height or altitude of the
triangle.
(Our solved example in mathguru.com uses this concept)
The term 'base' denotes any side and 'height' denotes the length
of a perpendicular from the vertex opposite the side onto the line containing
the side itself.
http://en.wikipedia.org/wiki/Triangle
The above explanation is copied from
Wikipedia, the free encyclopedia and is remixed as allowed under the Creative
Commons Attribution- ShareAlike 3.0 Unported License.