Question 660149
Triangle ABC has a horizontal side BC of length {{{8-3=5}}} which we can take as the base, with a height of {{{h=7-(-2)=9}}}
{{{drawing(300,300,-5,10,-4,11,
grid(0),
triangle(-4, 7,3, -2,8, -2),
locate(-4, 8,A),locate(3, -2,B),locate(8, -2,C),
green(line(-4,-2,-4,7)),locate(-4,3,h),
red(line(-5,-2,3,-2))
)}}} The area of triangle ABC is {{{base*height/2=5*9/2=45/2=22.5}}}
Dilating the triangle by a factor of {{{2}}},
dilates every side (and base and height) by a factor of {{{2}}},
and it increases the area by a factor of {{{2^2=4}}}.
So the area of the dilated triangle is
{{{4*45/2=highlight(90)}}}