Lesson#2 Toolkit for Exercise 12.8 (1) s=(++)/2 where ++=Perimeter of triangle (2) ∆ =√((−)(−)(−)) (3) Radius of incircle =∆/ (4) Radius of circumcircle (i) =/(2 sin )=/(2 sin )=/(2 sin ) (ii) =/(4 ∆) (5) Radii of escribed circle (6) Half angle formulas in terms of the sides. (7) Half angle formulas in terms of the sides. (8) Half angle formulas in terms of the sides. (i) tan /2=√(((−)(−))/((−))) (ii) tan /2=√(((−)(−))/((−))) (iii) tan /2=√(((−)(−))/((−))) Application of Trigonometry Chapter No 12 Exercise No 12.8 Mathematics part 1
