Answer: A Let the two sides of isosceles triangle be 'x' m each, then the third side = x√2 Given, 2x+x√2 = 6+3√3 By solving we get x=3. So side are 3,3 and 3√2. Area = 1/2 * 3*3 = 4.5 sq m.

Q. No. 8:

The area of the base of a right equilateral triangular prism is 9√3 cubic cm. If the height of prism is 16cm, find its whole surface area.

Answer: A Whole surface area of prism = Lateral surface area + 2(Area of base) Lateral surface area = Perimeter of base * height Area of base = 9√3 sq cm. = 1/2 * a * a√3/2 = √3/4 * a* a So, side of base a = 3*2 = 6cm Perimeter of base = 3*6 =18cm Lateral surface area = 18*16 = 288 sq cm. Whole surface area = 288+ 2*9√3 = 288+18√3 sq cm.

Q. No. 9:

The area of four walls of a room is 120 sq m and the length twice the breadth. If the height of the room is 4m, then find the area of the floor.

Answer: C Area of four walls = 2h(l+b) where, l=2b and h=4. 120= 8*3b => b=5 and l=10 Area of floor = l*b = 10*5 = 50 sq m.

Q. No. 10:

A metal cube of edge 12cm is melted and formed into three smaller cubes. If the edges of two smaller cubes are 6cm and 8cm, find the edge of the third smaller cube.

Answer: B Total inner cost = 2 * 22/7 * 7/2 * 22.5 * 3= Rs 1485.

Q. No. 12:

Water flows out through a circular pipe whose internal diameter is 2cm. at the rate of 6m/s into a cylindrical tank, the radius of whose base is 60 cm. By how much will the level of water rise in 30 minutes?