Q9 of 83 Page 367

Prove that area of a triangle = X base X altitude.


We know that when a parallelogram and a triangle lie on same base and between same parallel lines then, area of the triangle is half the area of the parallelogram.


Consider the figure,


Here,


Area(ΔABF) = 1/2 Area(||gm ABCD) (From above statement) –1


Area(||gm ABCD) = Base× Height –2


Sub –2 in –1


Area(ΔABF) = 1/2 × Base× Height


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