This is the basic and conceptual question from trigonometric ratios in which we have given a figure of right angled triangle ABC right angled at B and we have to find the length and BC and AB if ∠A = 45° and AC = 3√2 cm.

RS Aggarwal, Class 10, chapter 11, question no 22.

## From right angled △ABC,

(i) BC/AC=sin45∘

BC/3√2=1/√2

Or BC=3

(ii) By Pythagoras theorem

(AB)^2=(AC)^2−(BC)^2

=(3√2)^2−(3)^2

=18−9

=9

AB=3 cm.