STEP 1: find height $ h $
To find height $ h $ use Pythagorean Theorem:
$$ h^2 + \frac{ a^2 }{ 4 } = s^2 $$After substituting $a = 25\, \text{cm}$ and $s = 27\, \text{cm}$ we have:
$$ h ^ {\,2} + \frac{ \left( 25\, \text{cm} \right)^{2} }{ 4 } = \left( 27\, \text{cm} \right)^{2} $$ $$ h ^ {\,2} + \frac{ 625\, \text{cm}^2 }{ 4 } = \left( 27\, \text{cm} \right)^{2} $$ $$ h ^ {\,2} + \frac{ 625 }{ 4 }\, \text{cm}^2 = \left( 27\, \text{cm} \right)^{2} $$ $$ h ^ {\,2} = 729\, \text{cm}^2 - \frac{ 625 }{ 4 }\, \text{cm}^2 $$ $$ h ^ {\,2} = \frac{ 2291 }{ 4 }\, \text{cm}^2 $$ $$ h = \sqrt{ \frac{ 2291 }{ 4 }\, \text{cm}^2 } $$$$ h = \frac{\sqrt{ 2291 }}{ 2 }\, \text{cm} $$STEP 2: find volume $ V $
To find volume $ V $ use formula:
$$ V = \dfrac{ a ^{ 2 } \cdot h }{ 3 } $$After substituting $a = 25\, \text{cm}$ and $h = \dfrac{\sqrt{ 2291 }}{ 2 }\, \text{cm}$ we have:
$$ V = \dfrac{ 625\, \text{cm}^2 \cdot \frac{\sqrt{ 2291 }}{ 2 }\, \text{cm} }{ 3 }$$$$ V = \dfrac{ \frac{ 625 \sqrt{ 2291}}{ 2 }\, \text{cm}^3 }{ 3 } $$$$ V = \frac{ 625 \sqrt{ 2291}}{ 6 }\, \text{cm}^3 $$