Δ S C O : {(\frac{D}{2})}^{2} = (a_{1} + O B)^{2} - a_{1}^{2} = 2 a_{1} O B + (O B)^{2}

${\Delta SCO:\, \left(\frac{D}{2} \right)^2 = (a_1 + OB)^2 - a_1^2 = 2 a_1 OB + (OB)^2}$

Error