A triangle has corners at (-2 ,3 ), (3 ,2 ), and (5 ,-6 ). If the triangle is dilated by a factor of 2 about point #(1 ,-8 ), how far will its centroid move?

1 Answer
Dec 6, 2016

d=7.73" (shown in figure)"

Explanation:

"The original triangle and its centroid is shown in figure below."

enter image source here

"the original centroid can be calculated using:"

x=(-2+3+5)/3=6/3=2

y=(3+2+-6)/3=-1/3=-0,33

E(2,-0.33)

"Now dilate A(-2,3) by factor 2 with respect to D(1,-8)"

enter image source here

A(-2,3) rArr A'(1-3*2,3+11*2)

A'(1-3*2,-8+11*2)

A'(-5,14)" (shown in figure below)"

#enter image source here #

"Dilate B(3,2) by factor 2 with respect to D(1,-8)"

enter image source here

B(3,2) rArr B'(1+2*2,-8+10*2)

B'(1+2*2,-8+10*2)

B'(5,12)" (shown in figure below)"

enter image source here

"Dilate C(5,-6) by factor 2 with respect to D(1,-8)"

enter image source here

C(5,-6) rArr C'(1+4*2,-8+2*2)

C'(1+4*2,-8+2*2)

C'(9,-4)" (shown figure below)"

enter image source here

"Finally.."

"the dilated centroid can be calculated "

x'=(-5+5+9)/3=9/3=3

y'=(14+12-4)/3

y'=22/3=7,33

F(3,7.33)

enter image source here

"distance between E and F"

d=sqrt((3-2)^2+(7.33+0.33)^2)

d=sqrt(1+(7.66)^2)

d=sqrt(1+58.68)

d=sqrt(59.68)

d=7.73