Use your knowledge about isosceles triangles - two angles are always the same size. Find out what the total missing value is first: 180° - 50° = 130° Angles d and e must now both equal 130°.

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 ...