Angles In A Triangle

ANGLES IN A TRIANGLE ADD UP TO 180

When two angles within a triangle are known the third may be found using sutra By addition and Subtraction

By addition , 80+65= 145

By subtraction , 180-145=35

x = 35.

Vertically Opposite Angles

sutra : by mere observation 

Exterior angle:

if the side of the figure produced then the angle that line makes with the adjacent side is called the " Exterior Angle "

angle C is a exterior angle 

The exterior angle of a triangle is equal to the sum of the two  interior opposite angles

Angle on a straight line  also add up to 180 d+c =180