A triangle has corners at (8 ,3 )(8,3), (4 ,-6 )(4,6), and (-2 ,5 )(2,5). If the triangle is dilated by a factor of 5 5 about point #(1 ,-3 ), how far will its centroid move?

1 Answer
Aug 3, 2016

4/3sqrt{170}43170

Explanation:

The centroid of the triangle is originally at

({8+4+(-2)}/3,{3+(-6)+5}/3)=(10/3,2/3)(8+4+(2)3,3+(6)+53)=(103,23)

The distance of the centroid from (1,-3)(1,3) is

sqrt{(10/3-1)^2+(2/3-(-3))^2}=1/3sqrt{7^2+11^2}=1/3sqrt{170}(1031)2+(23(3))2=1372+112=13170

This distance is multiplied by a factor of 5 by the dilatation. The distance the centroid will move is
4 xx 1/3 sqrt{170} = 4/3sqrt{170}4×13170=43170