# Surface Area and Volumes (IMO- Mathematics Olympiad (SOF) Class 9): Questions 76 - 81 of 104

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## Question number: 76

» Surface Area and Volumes

MCQ▾

### Question

A spherical ball of lead, 9 cm in diameter is melted and recast into four spherical balls. The diameter of three of these are 3 cm, 2 cm, 2.5 cm is respectively. The radius of the fourth ball is________.

### Choices

Choice (4) Response

a.

8.79 cm

b.

6.79 cm

c.

7.79cm

d.

5.79 cm

## Question number: 77

» Surface Area and Volumes

MCQ▾

### Question

A cylindrical rod whose height is 12 times of its radius is melted and recast into spherical balls of same radius. The numbers of balls will be________

### Choices

Choice (4) Response

a.

9

b.

2

c.

7

d.

6

## Question number: 78

» Surface Area and Volumes

MCQ▾

### Question

How many metres of cloth, 4 m wide, will be required to make a conical tent, the radius of whose base is 14 m and height is 12 m?

### Choices

Choice (4) Response

a.

104.07 m

b.

115.05 m

c.

105.06 m

d.

106.06 m

## Question number: 79

» Surface Area and Volumes

MCQ▾

### Question

The area of an isosceles triangle having base x cm and one side y cm is________

### Choices

Choice (4) Response

a.

b.

c.

d.

## Question number: 80

» Surface Area and Volumes

MCQ▾

### Question

If the height of cone is thrice, then its volume is increased by________.

### Choices

Choice (4) Response

a.

b.

c.

d.

## Question number: 81

» Surface Area and Volumes

MCQ▾

### Question

The altitude drawn to the base of an isosceles triangle is of length 6 cm and the perimeter is 72 cm. the area of the triangle is ________

### Choices

Choice (4) Response

a.

b.

c.

d.

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