Given:
In a triangular based prism,
AB = AC = 10cm, BC = 12cm
and height of the prism CC' = 30cm
To find: Volume of the prism (V)
By formula,
Area of the isosceles triangular base = \(\frac b4\times\sqrt{4a^2-b^2}\)
= \(\frac{12cm}4\times\sqrt{4\times(10cm)^2-(12cm)^2}\)
= \(3cm\times\sqrt{400cm^2-144cm^2}\)
= \(3cm\times\sqrt{256cm^2}\)
= 3cm x 16cm
= 48cm2
Again, by formula
Volume of prism (V) = Area of the base x height
= 48cm2 x 30cm
= 1440cm2