UPSKILL MATH PLUS

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Answer variants:
\(3 \pi r^2\)
\(2 \pi r^2\)
23πr3
\(4 \pi r^2\)
43πr3
\(4 \pi r^3\)
1. A right circular cylinder just enclose a sphere of radius \(r\) units.

Calculate:

(i) the surface area of the sphere
 sq. units

(ii) the curved surface area of the cylinder
 sq. units

(iii) the ratio of the areas obtained in (i) and (ii) i:i
 
 
2. A shuttle cork used for playing badminton has the shape of a frustum of a cone is mounted on a hemisphere. The diameters of the frustum are \(5 \ cm\) and \(2 \ cm\). The height of the entire shuttle cork is \(7 \ cm\). Find its external surface area.
 
Answer:
 
The external surface area of the shuttle cork \(=\)  \(cm^2\)
 
[Note: Round off your answer up to two decimal places.]
 
 
3. An oil funnel of tin sheet consists of a cylindrical portion \(10 \ cm\) long attached to a frustum of a cone. If the total height is \(22 \ cm\), the diameter of the cylindrical portion be \(8 \ cm\) and the diameter of the top of the funnel be \(18 \ cm\), then find the area of the tin sheet required to make the funnel.
 
Answer:
 
The area of the tin sheet required to make the funnel \(=\)  \(cm^2\)
 
[Note: Round off your answer up to two decimal places.]