Question

A teacher brings clay i the classroom to teach the topic 'mensuration' . She forms a cylinder of radius 6 cm and height 8cm with the clay. Then she moulds that cylinder into a sphere. Find the radius of sphere formed . Do teaching aids enhance teaching learning process? Justify your answer.

Answer 1

Solution :-

The teacher first made the cylinder from clay and then she moulds the cylinder into a sphere. 

So, the volume of the cylinder will be exactly equal to the volume of the sphere.

Radius of the cylinder = 6 cm

Height of the cylinder = 8 cm

Volume of cylinder = πr²h

⇒ 22/7*6*6*8

⇒ 6336/7

= 905.14 cu cm

Volume of sphere = 4/3πr³

⇒ 905.14 = 4/3*22/7*r³

⇒ r³ = (905.14*7*3)/88

⇒ r³ = (905.14*21)/88

⇒ r³ = 19007.94/88

⇒ r³ = 215.999

⇒ r = 5.9999  or 6 cm (Approximately)

So, radius of the sphere is 6 cm.

It is true that teaching aids enhance teaching learning process. Some benefits of teaching aids are as follows

1) Teaching aids provide practical training with more power.

2) Teaching aids develop skills to fully and effectively in students.

3) Through teaching aids real experiences are available for students.

4) Teaching aids provide complete example for conceptual thinking.  

Answer 2

Answer:

$r ^{3} = 216$