Ftmdnydngdngd fbfdjj

The above triangle is an isosceles triangle

Reason

As we can see AB and DE are parallel to each other

As angle ABC is 80 degree

Therefore BCE is too 80 degree (as they both are alternate to each others)

Hence angle DCB is a 50 degree because in the straight DCE we have angle BCE as 80 degree and Angle ACD as 50 degree

Since a straight line has 180 degree therefore the remaining angle ACB is 50 degree(180-80-50)

Now in triangle BAC. Angle C is 50 degree and Angle B is 80 degree, since the total angle of a triangle is 180 degree therefore A is 50 degree that is angle BAC is 50 degree(180-50-80) .

Hence here we see that two opposite sides have same angle that is the reason its a ISOSCELES triangle

Answer BY AN INDIAN

THANK YOU

tube or goog would be a great resource to with that question