Asked by Adesuyi Similoluwa

A sector of a circle of radius is 7cm substending an angle of 27% at all he center of the circle is used to form a cone.
A. Find the base radius of the cone.
B. Calculate the area of base of the cone
Answered by oobleck
If the sector subtends an angle θ, then the arc length subtended is 7θ
That will be the circumference of the base of the cone, so its radius will be r = 7θ/2π.
Then, as usual, the area is πr^2
Answered by Reiny
If you make a sketch you will realize that the major arc length of the sector will be the circumference of the base of the the cone
circumference of original circle = 14π cm
So the length of the arc for your cone = (333/360)(14π) = 259/20 π cm

Then for your base of the cone:
2π r = 259/20 π
2r = 259/20
r = 259/40 cm or 6.475 cm

Now you have the radius of the base, just use your area formula.
Answered by Reiny
Go with oobleck, I used the major sector to form the cone,
it should be the minor arc.
Answered by oobleck
works for either arc. I also was ready to assume the major arc, since the angle subtended is so small.