A line segment has endpoints at (7 ,6 )(7,6) and (5 ,8 )(5,8). The line segment is dilated by a factor of 3 3 around (2 ,4 )(2,4). What are the new endpoints and length of the line segment?

1 Answer
May 7, 2017

The new emd points are (17,10)(17,10) and (11,16)(11,16)
The length of the line segment is =8.49=8.49

Explanation:

Let the end points beA=(7,6)A=(7,6) and B=(5,8)B=(5,8)

and C=(2,4)C=(2,4)

Let A' and B' be the new end points

Then,

vec(CA')=3vec(CA)

=3*<7-2,6-4> =3*<5,2> = <15,6>

A'=(15,6)+(2,4)=(17,10)

Similarly,

vec(CB')=3vec(CB)

=3*<5-2,8-4> =3*<3,4> = <9,12>

B'=(9,12)+(2,4)=(11,16)

The length of the line segment is

A'B'=sqrt((11-17)^2+(16-10)^2)

=sqrt((6)^2+(6)^2)

=sqrt72

=8.49

The length of the old line segment is

AB=sqrt((5-7)^2+(8-6)^2)

=sqrt(4+4)

=sqrt(8)

=2.83

A'B'=3*AB