Question

fid the measure of the central angle of the cutout sector.

Answer 1

The lateral surface area of the cone is the same as the area of the blue sector of the circle.
So the blue sector = 64pi.
The area of the circle is 100 pi.
Find the ratio and you can find the angle because full circle makes 360 degrees
What does 64pi make?
360 - that angle = angle of the cut out.

Answer 2

Cone surface area = PI * r * slant height
Is the radius of that circle 10 cm?

Answer 3

im completely lost on what to do with this

Answer 4

64pi / 100 pi = x degrees / 360 degrees
Find x.
360 - x is the angle of the cut out.

Answer 5

Seems that ranga thinks radius = 10 cm so area of entire circle = 100 PI
Area of remaining section = 64 PI so area of cut out section is 36 PI
So the cut out section is (36 PI / 100 PI) part of the circle and the angle would be 360° * .36
which equals 129.60 degrees
or 2.262 radians

Answer 6

@wolf1728 thanks for clearing that up

Answer 7

@ranga thanks for the help