Two corners of an isosceles triangle are at (1,3) and (5,8). If the triangle's area is 6, what are the lengths of the triangle's sides?

1 Answer

possible triangle with sides:92537=3.70974,92537=3.70974,41=6.40312
possible triangle with sides:413, 41, 1.89495

Explanation:

Distance between the two points
=(51)2+(83)2=41
Let this be the base b=41
Formula for Area of triangle:

Area=12bh
6=1241h

h=1241

The two equal sides can now be computed:
Let x be one of the sides
x=h2+(b2)2
x= (1241)2+(412)2
x=18292537
x=3.70974
First triangle with sides:
x=3.70974
x=3.70974
b=41=6.40312

For the second triangle:
the two equal sides are:
x=41
x=41
and the 3rd side b
compute the vertex angle of the isosceles triangle first:
Area=124141sinθ
6=124141sinθ
sinθ=1241
θ=17.0186
Using cosine law
b=x2+x22xxcosθ
b=412+41224141cos(17.0186)
b=1.89495 units

God bless....I hope the explanation is useful.