Question

In right angled triangle A = 90º and B = 30°. If AC = 2.5cm then find BC​

Answer 1

Solution:-

△ ABC is a right-angled triangle.

By Pythagoras theorem,

$AC {}^{2} = BC {}^{2} + AB {}^{2}$

${13}^{2} = {5}^{2} + AB {}^{2}$

$AB {}^{2} = - ( 5) {}^{2} + 13 {}^{2}$

$AB {}^{2} = - 25 + 169 \\ AB {}^{2} = 144 \\ AB = \sqrt{144} \\ AB = 12 \: cm$