Answer
As per dot product of 2 vectors A and B, with angle $\theta$ between them ,
$vec(A) vec(B) = |vec(A)|\times|vec(B)|\times cos\theta=vecA_{x}vecB_{x}+vecA_{y}vecB_{y}=0$
because , $cos\theta=0$ as $\theta=90^{\circ}$.
Work Step by Step
As per dot product of 2 vectors A and B, with angle $\theta$ between them ,
$vec(A) vec(B) = |vec(A)|\times|vec(B)|\times cos\theta=vecA_{x}vecB_{x}+vecA_{y}vecB_{y}=0$
because , $cos\theta=0$ as $\theta=90^{\circ}$.
