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Current time:0:00Total duration:1:59

- [Instructor] Use one rotation
to map quadrilateral ABCD to the other quadrilateral. So to map this one to
this one right over here. Use a number between zero
and 360 degrees to describe the angle. Counter-clockwise is positive. So we're going to want to
move is counter-clockwise to try and get it to map there. And the only option they
give us 'cause they want us to do it with one rotation
is the rotation tool. And so we have to think about
what do you we want to rotate around what point and if
we put it right over here, it looks like this point point
A does correspond to this point right over here. So if we were to rotate this
around, if we were to rotate this around not 90 but
it looks like 180 degrees around this point, point
A would show up over here, it feels like point let's see
is that right is that right or let's actually just try it out. Point A would show up over,
no no no that's not right, that doesn't seem to... Let's try it out. 'Cause if we rotated 180
degrees, oh actually I was right it did match up, that's why
this is interesting, it tests your visualization skills. So it did actually match
up and what I did is I put that point of rotation
exactly between those points but because it looked like
180 degrees around this point, so rotation by 180 degrees
about negative one negative one so the center of rotation is
negative one negative one, the angle of rotation is 180 degrees. Point A maps to this point
right over here, so point A maps to the point one negative
one, one negative one. And point C point C which is
diagonally opposite point A maps to this point right
over here, which is six negative six, six negative
six, six negative six and we got it right.