STEP 1: find angle $ \alpha $
To find angle $ \alpha $ use formula:
$$ \sin \left( \alpha \right) = \dfrac{ h }{ a } $$After substituting $ h = \frac{ 1371 }{ 100 } $ and $ a = \frac{ 1459 }{ 100 } $ we have:
$$ \sin \left( \alpha \right) = \dfrac{ \frac{ 1371 }{ 100 } }{ \frac{ 1459 }{ 100 } } $$ $$ \sin \left( \alpha \right) = \frac{ 1371 }{ 1459 } $$ $$ \alpha = \arcsin\left( \frac{ 1371 }{ 1459 } \right) $$ $$ \alpha = 69.9987^o $$STEP 2: find angle $ \beta $
To find angle $ \beta $ use formula:
$$ \alpha + \beta = 90^o $$After substituting $ \alpha = 69.9987^o $ we have:
$$ 69.9987^o + \beta = 90^o $$ $$ \beta = 90^o - 69.9987^o $$ $$ \beta = 20.0013^o $$