Question

sin 70° =
a)cos 60 b)sin 20 c)cos 20 d)sin 60​

Answer 1

Answer:

c) cos 20

Step-by-step explanation:

Let us say that a is an angle.

Then, sin a = cos 90 - a

Here, a = 70

So, sin 70 = cos 90 - 70 = cos 20

Answer 2

Answer:

(c) cos20°

Step-by-step explanation:

sinθ = cos(90-θ)

sin70° = cos(90-70)°

sin70° =  cos20°

∴ The value of sin70° is (c) cos20°