Answer
$$θ=\frac{\pi }{4}$$
Work Step by Step
To evaluate trigonometric functions without a calculator, it is necessary to use the unit circle. Doing this, we find that theta is:
$$\sin \left(θ\right)=\cos \left(θ\right) \\ \frac{\sin \left(θ\right)}{\cos \left(θ\right)}=1 \\ \tan \left(θ\right)=1 \\ θ=\frac{\pi }{4}$$
