問數學題~~~

number ONE

Circumference of a circular base: C(r)= 2πr
Since Circumference is given (18m), set 2πr=18m
2πr= 18m
2r= 18πm = D
r= 18/2πm
r= 9/πm

Surface Area of a Cone: A(r,s): πr²+πrs
the Slant height is given (4.5m), and Radius, from the circumference, is 9/πm

A= π(9/π)²+ π(9/π)(4.5) -14.0 (14m because it was the surface area of the door.)
A= 81/π+ 40.5- 14.0
A= 81/π+ 26.5
A≈ 52.3m²

number TWO

This question is rather pathetic by my judgement. I could not tell rather if the Diamter or Surface Area were those from the cone or some random numbers. However, if the question is related to the previous question, then the solution will be the following:

Volume of a Sphere with diameter and Surface Area: V(A,D) = 1/6AD

Surface Area A was 81/π+ 26.5 from the previous question, and from the circumference, the diameter is 18πm. Thus:

V= 1/6 (81/π+ 26.5)(18π)
V= 1/6 (1458+ 477π)
V= 243+ 159π/2
V≈ 492.8m²