STEP 1: find angle $ \alpha $
To find angle $ \alpha $ use formula:
$$ \sin \left( \frac{ \alpha }{ 2 } \right) = \dfrac{ d_2 }{ d_1 } $$After substituting $ d_2 = 16 $ and $ d_1 = 26 $ we have:
$$ \sin \left( \frac{ \alpha }{ 2 } \right) = \dfrac{ 16 }{ 26 } $$ $$ \sin \left( \frac{ \alpha }{ 2 } \right) = \frac{ 8 }{ 13 } $$ $$ \frac{ \alpha }{ 2 } = \arcsin\left( \frac{ 8 }{ 13 } \right) $$ $$ \frac{ \alpha }{ 2 } = 37.9799^o $$$$ \alpha = 37.9799^o \cdot 2 $$$$ \alpha = 75.9597^o $$STEP 2: find angle $ \beta $
To find angle $ \beta $ use formula:
$$ \alpha + \beta = 90^o $$After substituting $ \alpha = 75.9597^o $ we have:
$$ 75.9597^o + \beta = 90^o $$ $$ \beta = 90^o - 75.9597^o $$ $$ \beta = 14.0403^o $$