(i) The area of any triangle is equal to four times the area of the triangle formed by joining the midpoints of its sides.
In the above figure
(ii) The diagonals of a rhombus bisects at right angles.
(iii) The internal bisectors of angles of a triangle are concurrent.
(iv) The line segment joining the midpoints of two sides of a triangle is a parallel to the third and half of its length.
(v) The altitude of a triangle are concurrent.
(vi) Medians of a triangle are concurrent.
(vii) The perpendicular bisectors of the sides of a triangle are concurrent .
(viii) An angle in a semicircle is a right angle.
The orthocenter , Centroid and the circumcenter of a non-equilateral triangle are collinear and the aligned line is called Euler line.