find the value of C for the pic below

Find the value of C for the pic below

$$0.828= \dfrac{ \left(\dfrac{2-c}{2}\right)^{\dfrac{1}{2}} \cdot \left( \dfrac{4-c}{2}\right)^{\dfrac{1}{2}} } {c} \cdot \underbrace{ \left( \dfrac{2}{3.1}\right)^{ \underbrace{ \left(\dfrac{1}{2}+\dfrac{1}{2}-1 \right) }_{=0} } }_{=1} \qquad \boxed{a^0 = 1}$$

$$\small{\text{ $ \begin{array}{rcl} 0.828 &=& \dfrac{ \left(\dfrac{2-c}{2}\right)^{\dfrac{1}{2}} \cdot \left( \dfrac{4-c}{2}\right)^{\dfrac{1}{2}} } {c}\cdot 1\\ \\ 0.828 &=& \dfrac{ \left(\dfrac{2-c}{2}\right)^{\dfrac{1}{2}} \cdot \left( \dfrac{4-c}{2}\right)^{\dfrac{1}{2}} } {c}\\\\ 0.828\cdot c &=& \left(\dfrac{2-c}{2}\right)^{\dfrac{1}{2}} \cdot \left( \dfrac{4-c}{2}\right)^{\dfrac{1}{2}}\\\\ 0.828\cdot c &=& \sqrt{ \dfrac{2-c}{2} } \cdot \sqrt{ \dfrac{4-c}{2}\right) } \quad | \quad ()^2\\\\ 0.828^2\cdot c^2 &=& \left( \dfrac{2-c}{2} \right) \cdot \left( \dfrac{4-c}{2}\right) \\\\ 4\cdot 0.828^2\cdot c^2 &=& \left( 2-c \right) \cdot \left( 4-c \right) \\\\ 2.742336 \cdot c^2 &=& 8-2c-4c+c^2 \\\\ 2.742336 \cdot c^2 &=& 8-6c+c^2 \\\\ 2.742336 \cdot c^2 - c^2 + 6c - 8 &=& 0 \\\\ c^2 \cdot (2.742336 -1 ) + 6c - 8 &=& 0 \\\\ 1.742336 \cdot c^2 + 6c - 8 &=& 0 \\\\ c_{1,2} &=& \dfrac{-6 \pm \sqrt{6^2-4\cdot 1.742336 \cdot (-8) } }{ 2\cdot 1.742336 } \\\\ c_{1,2} &=& \dfrac{-6 \pm \sqrt{36+55.7547520000} }{ 2\cdot 1.742336 } \\\\ c_{1,2} &=& \dfrac{-6 \pm \sqrt{91.7547520000} }{ 2\cdot 1.742336 } \\\\ c_{1,2} &=& \dfrac{-6 \pm 9.57887007950}{ 2\cdot 1.742336 } \\\\ c_{1,2} &=& \dfrac{-6 \pm 9.57887007950}{ 3.484672 } \\\\ \end{array} $}}$$

$$\small{\text{ \begin{array}{rcl|rcl} $ c_1 &=& \dfrac{-6 + 9.57887007950}{ 3.484672 } \quad & \quad c_2 &=& \dfrac{-6 - 9.57887007950}{ 3.484672 } \\\\ c_1 &=& 1.02703212225 \quad & \quad c_2 &=& -4.47068478167$ no solution $ $ \end{array} }}\\\\ c = 1.02703212225$$