Question

∆ABC is right angled at C and AB=40 unit, BC=20 unit. then angle B is- (a)30° (b)40° (c)60° (d)90°

Answer 1

Answer:

(c)60°

Step-by-step explanation:

Using trigonometry ,

We know that ,

cos ∅ = adjecent side / hypotenuse

∴ cos B = BC / AB

            = 20/40    

            = 1/2

∴B = $cos ^ -1$(1/2)

∴ B = 60° .