Answer:
Option 4
Explanation:
"Angle formed between a secant and a tangent at a point outside a circle is equal to half of the difference of the measure of the intercepted arcs"
By applying this theorem in the figure given in the picture,
m∠RST =
![(1)/(2)[\text{m(arc TU - m(arc RT))}]](https://img.qammunity.org/2022/formulas/mathematics/high-school/f6y5ocdfbvl0oxlb411v98jnfkhy11hb3t.png)
![x=(1)/(2)(155-65)](https://img.qammunity.org/2022/formulas/mathematics/high-school/saiplvsv4ndnn54ew01eyar5mwieth7q0o.png)
![x=(1)/(2)(90^0)](https://img.qammunity.org/2022/formulas/mathematics/high-school/1a56jlgb6paqpqwvzsk28nx98xkancl1mk.png)
![x=45^0](https://img.qammunity.org/2022/formulas/mathematics/high-school/af7hz2x440qdnizmi259um53vmpgfmx3i0.png)
Therefore, Option 4 is the correct option.