Calculate the Predicted Atomic Radius for Radioactive Polonium,Po,given the Radius

Calculate the predicted atomic radius for radioactive polonium,Po,given the radius of selenium,Se, (0.116 nm) and tellurium,Te, (0.143 nm) .

A) 0.027 nm
B) 0.089 nm
C) 0.130 nm
D) 0.157 nm
E) 0.170 nm