Printing value of volume and surface area
echo ( " Volume ▁ Of ▁ Cone ▁ : ▁ " ) ; echo ( volume ( $ radius , $ height ) ) ; echo ( " STRNEWLINE " ) ; echo ( " Surface ▁ Area ▁ Of ▁ Cone ▁ : ▁ " ) ; echo ( surface_area ( $ radius , $ slant_height ) ) ; ? >