MBND is a parallelogram as BN=MD and BN║MD.
A parallelogram is a quadrilateral whose both pair of opposite side are equal and parallel. Few examples of parallelograms are square, Rhombus and rectangle.
Given ABCD is a parallelogram and ∠A=90°
Now we have to prove that MBND is a parallelogram
Given BN⊥AC and DM⊥AC
Since BN and DM are both perpendicular to the same straight line AC then we cam say that BN║DM.
Again we know from the properties of parallelogram that the diagonal divides a parallelogram into two equal triangles.
Therefore the diagonal AC divides the parallelogram into two equal triangles ΔABC and ΔADC.
Now we know that the area of a triangle is given by
×base ×height .
Area of ΔABC =Area of ΔADC
Since BN⊥AC and DM⊥AC
∴
×BN×AC=
×DM×AC
This above equation can be simplified as
BN=MD
Hence BMND is a parallelogram as we know from the properties of parallelogram that when a pair of opposite sides are equal and parallel in a quadrilateral it is a parallelogram.
To learn more about properties of parallelograms:
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