If a side of a triangle is produced, the angle so formed is equal to the sum of the two_______________.
By the exterior angle property of a triangle the exterior angle of a triangle so formed is equal to the sum of two interior opposite angles.
If the sides of a triangle are produced in order, prove that the sum of the exterior angles so formed is equal to four right angles.
If the sides of a triangle are produced in order, then the sum of the three exterior angles so formed is: