Sphere in cone

A sphere is inscribed in the cone (the intersection of their boundaries consists of a circle and one point). The ratio of the ball's surface and the area of the base is 4:3. A plane passing through the axis of a cone cuts the cone in an isosceles triangle. Find the size of the angle for the base of this triangle.

Correct answer:

A =  60 °

Step-by-step explanation:

G=1 G:S1 = 4:3 S1=43 G=43 1=43 1=43=0.75  S1 = π r12  r1=S1/π=0.75/3.14160.4886  G = 4 π r22  r2=4πG=4 3.141610.2821  tan α= r2:r1 α=arctan(r2/r1)=arctan(0.2821/0.4886)0.5236 rad  α2=2 α=2 0.52361.0472 rad  A=α2  °=α2 π180   °=1.0472 π180   °=60  °=60

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