Question #54074

Question

291 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2018-02-07T18:58:50

#x=40#

#"the exterior angle "120^@" is equal to the sum of the"#
#"opposite interior angles 2x and x"#

#rArr2x+x=120#

#rArr3x=120rArrx=40#

Answer 2 · 2018-02-07T20:00:40

#x=40^°#

A slightly different way to do it.

Angles on a straight line add up to #180^°#. So the third angle in our triangle is #180-120=60#.

But the angles of a triangle also add up to #180#. So

#2x+x+60=180#

#rArr 3x=120#

#rArrx=40^°#