Step-by-step explanation:
[tex] \because \sin \theta = \cos \theta \\ \\ \therefore \: \sin \theta = \sin(90 \degree - \theta) \\ \\ \therefore \: \theta = 90 \degree - \theta \\ \\ \therefore \: \theta + \theta= 90 \degree \\ \\ \therefore \: 2\theta = 90 \degree \\ \\\therefore \: \theta = \frac{90 \degree }{2} \\ \\ \huge \orange{\boxed{\therefore \: \theta = 45 \degree}}\\ \\[/tex]