Question 65977
Let the second angle of the triangle be x deg.

so the first angle measures = 5x deg.

measure of the exterior angle at the third vertex = 120 deg

The exterior angle = sum of interior opposite angles.

==> 120 = x + 5x
==> 120 = 6x
==> 120/6 = 6x/6
==> 20 = x

Therefore the angles of the triangle are 20 deg, 100 deg and 60 deg[as the sum is always = 180 deg]


Good Luck!!!