In: Math
Draw a convex quadrilateral ABCD, where the diagonals intersect at point M. Prove: If ABCD is a parallelogram, then M is the midpoint of each diagonal.
Convex quadrilaterals: In a convex quadrilateral, all interior angles are less than 180° and the two diagonals both lie inside the quadrilateral.
CYCLIC QUADRILATERAL: The four sides are tangents to an inscribed circle. A convex quadrilateral is tangential if and only if opposite sides have equal sums.
PARELLELOGRAM: One special kind of polygons is called a parallelogram. It is a quadrilateral where both pairs of opposite sides are parallel.
There are six important properties of parallelograms to know:
△ACD≅△ABC.
the four sides are tangents to an inscribed circle. A convex quadrilateral is tangential if and only if opposite sides have equal sums.