Not Rendering Specific Latex

[abhinayVarma]

If $$\triangle ABC\sim \triangle PQR$$ and $$\angle A={ 60 }^{ \circ }$$ , $$\angle R={ 70 }^{ \circ }$$. Then, $$\angle B=$$ ? I have tried rendering this string , but it doesn't work. Please let me know if there is any solution since on other rendering machines it renders with charm.