STEP 1: find diagonal $ d1 $
To find diagonal $ d1 $ use formula:
$$ d_1^2 + d_2^2 = 4 \cdot a^2 $$After substituting $d_2 = 4\, \text{cm}$ and $a = 4\, \text{cm}$ we have:
$$ d_1 ^ {\,2} + \left( 4\, \text{cm} \right)^{2} = 4 \cdot \left( 4\, \text{cm} \right)^{2} $$ $$ d_1 ^ {\,2} + 16\, \text{cm}^2 = = 64\, \text{cm}^2 $$ $$ d_1 ^ {\,2} = = 64\, \text{cm}^2 - 16\, \text{cm}^2 $$ $$ d_1 ^ {\,2} = 48\, \text{cm}^2 $$ $$ d_1 = \sqrt{ 48\, \text{cm}^2 } $$$$ d_1 = 4 \sqrt{ 3 }\, \text{cm} $$STEP 2: find angle $ \alpha $
To find angle $ \alpha $ use formula:
$$ \sin \left( \frac{ \alpha }{ 2 } \right) = \dfrac{ d_2 }{ d_1 } $$After substituting $d_2 = 4\, \text{cm}$ and $d_1 = 4 \sqrt{ 3 }\, \text{cm}$ we have:
$$ \sin \left( \frac{ \alpha }{ 2 } \right) = \dfrac{ 4\, \text{cm} }{ 4 \sqrt{ 3 }\, \text{cm} } $$ $$ \sin \left( \frac{ \alpha }{ 2 } \right) = \frac{\sqrt{ 3 }}{ 3 } $$ $$ \frac{ \alpha }{ 2 } = \arcsin\left( \frac{\sqrt{ 3 }}{ 3 } \right) $$ $$ \frac{ \alpha }{ 2 } = 35.2644^o $$$$ \alpha = 35.2644^o \cdot 2 $$$$ \alpha = 70.5288^o $$STEP 3: find angle $ \beta $
To find angle $ \beta $ use formula:
$$ \alpha + \beta = 90^o $$After substituting $ \alpha = 70.5288^o $ we have:
$$ 70.5288^o + \beta = 90^o $$ $$ \beta = 90^o - 70.5288^o $$ $$ \beta = 19.4712^o $$