V
P
A
4 Here is an explanation that the angle sum of triangle ABC is 180°.
The reasons for each line are missing.
Give the reasons.
1. Angle A of the triangle = angle PCA
2. Angle B of the triangle = angle QCB
3. Angle PCA + angle C of the triangle + angle QCB = 180°
Hence angle A + angle B+ angle C = 180°
С
B
5 Show that the interior angles of this shape add up to 360°.