STEP 1: find angle $ \alpha $
To find angle $ \alpha $ use formula:
$$ \sin \left( \alpha \right) = \dfrac{ h }{ a } $$After substituting $h = 6.93\, \text{cm}$ and $a = 8\, \text{cm}$ we have:
$$ \sin \left( \alpha \right) = \dfrac{ 6.93\, \text{cm} }{ 8\, \text{cm} } $$ $$ \sin \left( \alpha \right) = 0.8663 $$ $$ \alpha = \arcsin\left( 0.8663 \right) $$ $$ \alpha = 60.0257^o $$STEP 2: find angle $ \beta $
To find angle $ \beta $ use formula:
$$ \alpha + \beta = 90^o $$After substituting $ \alpha = 60.0257^o $ we have:
$$ 60.0257^o + \beta = 90^o $$ $$ \beta = 90^o - 60.0257^o $$ $$ \beta = 29.9743^o $$STEP 3: find diagonal $ d2 $
To find diagonal $ d2 $ use formula:
$$ \sin \left( \frac{ \beta }{ 2 } \right) = \dfrac{ h }{ d_2 } $$After substituting $\beta = 29.9743^o$ and $h = 6.93\, \text{cm}$ we have:
$$ \sin \left( \frac{ 29.9743^o }{ 2 } \right) = \dfrac{ h }{ d_2 } $$ $$ \sin( 14.9871 ) = \dfrac{ 6.93\, \text{cm} }{ d_2 } $$ $$ 0.2586 = \dfrac{ 6.93\, \text{cm} }{ d_2 } $$ $$ d_2 = \dfrac{ 6.93\, \text{cm} }{ 0.2586 } $$ $$ d_2 = 26.7979\, \text{cm} $$