Since the triangular face is isosceles, the altitude bisects the base.
The slant height can be calculated as:
⇒√(√353)2−82⇒√353−64⇒√289=17
Given the slant height, we have to calculate the height of the pyramid. Hence,
h2=172−82⇒h2=289−64⇒h=√225=15
Now, the dimensions of the pyramid are: a=16 cm, h=15 cm
Volume =13(16)2.15=13×256×15=1280 cm3