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Volume & Surface Areas

1.

Curved surface area of a cone is 308 cm⊃2; and its slant height is 14 cm.

Answer: B

Curved surface area=πrl
So r=7 cm
Now total surface area=πr⊃2;+πrl=462 cm⊃2;

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2.

The plastic paint in a Asian paint container is sufficient to paint an area equal to 93.75m⊃2;. How many blocks of dimensions 22.5 cm × 10 cm × 7.5 cm can be painted out of this container

Answer: D

Total surface area of one block = 2(lb + bh + lh)
= [2(22.5 ×10 + 10 × 7.5 + 22.5 × 7.5)] cm
= 2(225 + 75 + 168.75) cm⊃2;
= (2 × 468.75) cm⊃2;
= 937.5 cm⊃2;
Let n blocks can be painted out by the paint of the container.
Area of n bricks = (n ×937.5) cm⊃2; = 937.5n cm⊃2;
Area that can be painted by the paint of the container = 93.75 m2= 937500 cm⊃2;
 937500 = 937.5n
n = 1000
Therefore, 100 blocks can be painted out by the paint of the container

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3.

The length, breadth and height of a room are 12 m, 10 m, and 9m respectively. Find the area of  our walls of room?

Answer: B

Area of the walls is given by =2(BH+LH) +LB=2(90+108)+120=516 m⊃2;

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4.

A solid with a vertex and a base that is formed by a simple closed curve is a

Answer: B

No answer description available for this question.

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5.

A basketball has a volume of 5600cm⊃3;. its radius is

Answer: C

No answer description available for this question.

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