What is the value of x? º A triangle with base on an extended line. Two angle measures are given. Top interior angle is twenty-eight degrees. Lower left exterior angle is seventy-one degrees. Lower right interior angle is labeled x degrees.
All interior angles of a triangle must have a sum of 180°. Interior angle of a triangle and its corresponding exterior angle must have a sum of 180° when its line is extended.
Top interior angle is 28° Lower left exterior angle is 71° Lower right interior angle is x°
Get the left interior angle. Exterior angle + Interior angle = 180° 71° + Interior angle = 180° Interior Angle = 180° - 71° Interior Angle = 109°
Top Interior angle + Left Interior Angle + Right Interior angle = 180° 28° + 109° + x° = 180° x = 180° - 28° - 109° x = 180° - 137° x = 43°
