find the value of C for the pic below

Find the value of C for the pic below

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

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

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