**Problem 1:** The base of a right prism is a triangle. If the lengths of the sides are 5cm., 12cm. and 13cm. and volume of the prism is 450cm3, then the total surface area of the prism is?

Solution:

Area =

=

Volume =Area * Height

450 = 30*h

h=15cm

Lateral surface area = Perimeter of base * Height

=(5+13+12)*15

=30*15 = 450

Total surface area of prism =Lateral surface area+2(area of base)

450 + 2*30 =

**Problem 2:** Find the total surface area of the cube of side 3.5 cm?

Solution:

Total surface area = = = 73.5

Problem 3: The diagonal of a cube is m. Find its volume?

Solution:

a=5

**Problem 3:** A cuboidal brick has a length, breadth, and height of 25cm, 15cm and 5cm respectively. Find its total surface area.

Solution:

Total surface area of cuboid = 2(lb+bh+lh)

= 2(375+75+125)

= 2*575 = 1150

**Problem 4:** The base of a right pyramid is a square of side 40cm. If the volume of the pyramid is 8000cm3, then its height is?

Solution:

Volume =

Area of base = Area of square = 40*40 = 1600

8000=

h = 15