Question

Answer 1

a, Đổi 0,5dm=5cm

Hệ thức lượng: \(BC=\dfrac{AB^2}{BH}=33,8\left(cm\right)\)

PTG: \(AH=\sqrt{AB^2-BH^2}=12\left(cm\right)\)

\(\sin B=\dfrac{AH}{AB}=\dfrac{12}{13}\approx0,9231\\ \sin C=\dfrac{AB}{BC}=\dfrac{5}{13}\approx0,3846\)

b, \(BC=BH+HC=7\left(cm\right);AC=\sqrt{CH\cdot BC}=2\sqrt{7}\left(cm\right)\\ AB=\sqrt{BH\cdot BC}=\sqrt{21}\left(cm\right)\)

\(\sin B=\dfrac{AC}{BC}=\dfrac{2\sqrt{7}}{7}\approx0,7559\\ \sin C=\dfrac{AB}{BC}=\dfrac{\sqrt{21}}{7}\approx0,6547\)