Question

Maths
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1. In a cylinder, radius is doubled and height is halved, then the curved surface area will be____________.

2. The radii of two cylinders are in the ratio 2:3 and their heights are in the ratio of 5.3 the ratio of their volumes is _________.

3. The total surface area of a cone whose radius is 2r and slant height 2l is_________.

4. The radii of two cylinders are in the ratio 2:3 and can be put in a room of dimensions 10m x 10m x 5m is __________.​

Answer 1

Explanation:

1)Area of curved surface area = 2pi r h

A.T.Q : 2pi 2r h/ 2 = 2pi r h

Ans. 2pi rh (same)

2) Ratio of Volume of two cylinder =

= 22/7 × 20 ÷ 22 /7 ×27

= 20/27 =20:27

3) Total surface area = pi r l +pi r 2

=22/7×2r × 2l + 22/7 × 2r ×2

= pi ×2× 2r ( l +1)

=pi4 r ( l +1)

4) sory , I dont understand this part :0

Answer 2

1. Unchanged
2.20:27
3. 4pi r l
4. Depends upon actual dimensions