Question

The length, breadth and height of a room are 5m, 4m and 3m respectively. Find the cost of white washing the walls of the room and the ceiling at the rate of ₹ 7.50 per m2. OR The curved surface area of right circular cylinder of height 14cm is 88cm2. Find the diameter of the base of the cylinder.​

Answer 1

Answer:

Step-by-step explanation:

$Length, \:breadth\: and\: height\: of\: a\: room\: are\: 5 m\:, 4 m\: and\: 3 m.$

$Area \;of\: four\; walls\: of\: the\: room\: =2h(l + b)$

$=2*3(5+4)$  

$=6(9)$

$=54 s q m$

$Area \:of\: the\: ceiling\: =l *b$

$5*4\\=20sq cm$

$Total\: area\; of\: the\: four\: walls\: and\: the\: ceiling\: of\: the\: room\:$

$=54+20\\=74sqcm$

$Cost\: of\: white\: washing\: = rupees \: 7.50 \;per\: sq m$

$Total\:cost\: of\; white\; washing\; =\:74*7.50= Rs\: 555$

$Height\: (h)\: of\: cylinder\: =\; 14cm$

$Let\; the \:diameter\: of\: cylinder\; be\: d.$

Curved Surface Area of Cylinder = 88cm square

$2\pi rh = 88 cm\: square$

$\pi dh = 88 \:cm \:square. (d = 2r)$

$22/7 * d *14 = 88 cm$

$d=2\:cm$

$Therefore ,the\; diameter\; of\: the\: base\; of\: the\: cylinder\: is\; 2 \:cm$

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