An isosceles triangle is a triangle that has 2 equal sides and 2 equal angles.
side XY = side XZ ∠Y = ∠Z Since ∠Y = a° then ∠Z = a°
Because interior angles of a triangle sum up to 180°, we simply need to find the difference between 180° and the 2 known angles to solve for the measure of angle X.
25 because the 8 values must times with 7 and will get 56. when the ninth value added , let the ninth value as y , 56+y , the new mean is 9 . so it will be like this , 56+y over 9 times with 9
