Example 3 - Chapter 13 Class 9 Surface Areas and Volumes

Transcript

Example 3 Savitri had to make a model of a cylindrical kaleidoscope for her science project. She wanted to use chart paper to make the curved surface of the kaleidoscope. (see Fig ). What would be the area of chart paper required by her, if she wanted to make a kaleidoscope of length 25 cm with a 3.5 cm radius? You may take = 22/7. Kaleidoscope is of form cylinder Area of chart paper required = Curved Surface Area of cylinder = 2 rh = 2 22/7 3.5 25 cm2 = 550 cm2 Thus, Area of chart paper required = 550 cm2