Question

|a| =13 |b| = 5 and a.b = 60 then |a*b| is​

Answer 1

Answer:

cos theta=a.b/|a| |b|

cos theta=60/(13)(5)

=60/65

=12/13

then sin theta = √1-cos² theta

sin theta = √1-(12/13)²

sin theta=5/13

NOW

|a×b|=|a||b| sin theta

=13×5×5/13

=5×5

=25