Question

students of a Vidyalaya were asked to participate in the competition for making and decorating pen holders in the shape of a cylindrical with a base in cardboard cardboard if there were 35 cometitors how much card was required to be bought for the competition​

Answer 1

Answer:

• Radius = 3 cm
• Height of penholder =10.5 cm

Surface area of penholder = CSA of perimeter + Area of base of perimeter.

$\\ \sf \: 2\pi \: rh + \pi {r}^{2} \\ \\ \\ \implies \sf \: \bigg(2 \times \frac{22}{7} \times 3 \times 10.5 \bigg) + \frac{22}{7} \times {(3)}^{2} \: \: {cm}^{2} \\ \\ \\ \implies \sf \: 132 \times 15 + \frac{198}{7} \: \: {cm}^{2} \\ \\ \\ \implies \sf \: 198 + \frac{198}{7} \: \: {cm}^{2} \\ \\ \\ \implies \sf \: \frac{1584}{7} \: \: {cm}^{2}$

$\therefore\:\:$ Area of cardboard sheet used by 1 competitor :

$\\ \implies \sf \blue{ \frac{1584}{7} \: \: {cm}^{2} }$

=> Area of cardboard sheet used by 35 competitors :

$\\ \implies \sf \: \bigg( \frac{1584}{7} \times 35 \: \bigg) \: \: {cm}^{2} \\ \\ \\ \implies \sf \red{7920 \: \: {cm}^{2} }$