Interior angles in a triangle add up to 180˚. Triangles close triangleA polygon with three straight sides. have three sides, therefore they have three angles. Interior angles in a triangle sum to a ...

An obtuse angle is between \(90^\circ\) and \(180^\circ\). To estimate the size of an angle, try thinking in terms of counting in quarter turns, or right angles. For example, the angle in the ...