Answer
$\sin 70^{\circ}=\cos 20^{\circ}$
Work Step by Step
The trigonometric ratios are as follows: $\sin \theta= \dfrac{opposite}{hypotenuse}$ ; $\cos \theta= \dfrac{Adjacent}{hypotenuse}$ and $\tan \theta= \dfrac{Opposite}{Adjacent}$
Since,
$\sin \theta=\cos (90^{\circ}-\theta)$
So, $\sin 70^{\circ}=\cos (90^{\circ}-70^{\circ})=\cos 20^{\circ}$
Our required answer is: $\sin 70^{\circ}=\cos 20^{\circ}$
