The area of a sector is 9pi cm^2 . The sector cover 1/4 of the entire circle. Find the radius of the circle. Thank you.

Given:

The area of a sector =

The sector cover of the entire circle.

To find:

The radius of the circle.

Solution:

Let r be the radius of the circle. Then, the area of the circle is:

It is given that the sector cover of the entire circle. So, the area of the sector is equal to of the area of the entire circle.

Multiply both sides by 4.

Divide both sides by .

Taking square root on both sides.

Radius of a circle cannot be negative. So, .

Therefore, the radius of the circle is 6 cm.

answer

a,b, and d

explanation

a reflection angle is more than

but less than;

an angle that measures

is a reflex angle.(true)

an angle that measures less than

is acute.(true)

provided we are considering angles greater or equal to zero.

an acute angle lies in the range.

an obtuse angle is less than 180° but more than 90°

an angle that measures 300° is obtuse (false)

an angle that measures 65° is an acute angle.(true)