# Mathematics

A sector of a circle radius 8cm subtends and and angle 90°a at the centre of a circle. If the sector is folded without overlap to form the curved surface of a cone, find the 1. Base radius 2. Height 3. Volume of the cone.

1. 👍
2. 👎
3. 👁
1. s = rθ so the circumference of the base of the cone is 8*π/2 = 4π
Thus the radius of the base is 4π/2π = 2 (1/4 the radius of the original circle)
The slant height is the original circle radius.
so the height of the cone is √(8^2-2^2) = √60
as always, the volume v = 1/3 πr^2 h

1. 👍
2. 👎
👤
oobleck
2. I don't like ur answer
it's not well explanatory

1. 👍
2. 👎

## Similar Questions

1. ### Math

Find the radius of the circle if an arc of length 5 ft on the circle subtends a central angle of 135°. (Round your answer to two decimal places.)

2. ### maths

calculate the area of a sector of a circle which subtends an angle of 45° at the centre of the circle, radius 14cm

3. ### Math

How would I calculate the area of a sector of a circle with radius 2 m that subtends an angle pi/3

4. ### Math

(b) what angle does an arc 5.5cm in length subtends at the centre of length subtend at the centre of a circle of radius 1/2m?

1. ### pre-calc

Find an angle between 0 and 2ð that is coterminal with the given angle. -8pi/3 A sector of a circle has a central angle of 60°. Find the area of the sector if the radius of the circle is 3 mi.

2. ### Mathematics

A sector of a circle of radius 7cm subtends angle 270° at the centre. Calculate a. Length of arc b. Area of sector c. Perimeter of sector

3. ### math

A sector of a circle subtending an angle 300 degrees at the centre is used to form a cone with base radius 6cm. Find the (a.)radius of the circle (b.)volume of the cone (c.)area of the minor sector of the circle

4. ### Maths

The angle of a sector of a circle with radius 42cm is 120 degree.if the sector is cut out and used to make a cone,what is the curved surface area of the cone?

1. ### maths

A sector of a circle of a radius 6cm subrends angle of 105 at the centre of a circle.calculate the perimeter of the sector and the area of the sector?

2. ### Maths

A sector of a circle of radius 7cm subtending an angle of 270 degree at centre of the circle is use to form a cone? (A)find the base radius of the cone. (B)calculate the area of the base of the cone.

3. ### TRIG HELP ASAP

I really need help on this problem. A sector has area of 15 in^2 and central angle of 0.2 radians. Find the radius of the circle and arc length of the sector

4. ### geometry

11. Infinitely many different sectors can be cut from a circular piece of paper with a 12-cm radius, and any such sector can be fashioned into a paper cone with a 12-cm slant height. (a) Show that the volume of the cone produced