Question

A cylindrical pillar is 50 cm in diameter and 4.9m in height. find the cost of painting the curved surface area of the pillar at the rate of 15.80 per m2.


plzz answer this question urgent

Answer 1

$\bf\huge\underline\green{Solution}$

Given

• Diameter of a cylinder is 50 cm so it's radius would be 50/2 that is 25 cm or 0.25 m
• Height of the cylinder is 4.9 m
• Rate of painting per m² is 15.80 rupees

To find

• The cost of painting it's curved surface area

Solution

By applying the formula of curved surface area of a cylinder let's find it's cs area firstly

$\large\boxed{\purple{Formula\:=\:2\:\times\:\pi\:\times\:rh}}$

Substituting the values of pie , radius and height in the formula we get ,

$\sf{Curved\:surface\:area\:=\:2\:\times\:\dfrac{22}{7}\:\times\:0.25\:\times\:4.9}$

$\sf{Curved\:surface\:area\:=\:2\:\times\:\dfrac{22}{7}\:\times\:\dfrac{1}{4}\:\times\:\dfrac{49}{10}}$

$\sf{Curved\:surface\:area\:=\:11\:\times\:\dfrac{1}{2}\:\times\:\dfrac{7}{5}}$

$\sf{Curved\:surface\:area\:=\:\dfrac{77}{10}\:or\:7.7\:m}$

Now cost of painting 7.7 m would be

$\large\boxed{\purple{Formula\:=\:Area\:\times\:Rate}}$

Cost of painting 7.7 m = 7.7 m × 15.80

Cost of painting 7.7 m = 121.66 rupees

$\bf\huge\underline\blue{Some\:Formulas}$

• Curved surface area of a cylinder = 2πrh
• Total surface area of cylinder = 2πr(h + r )
• Volume of cylinder = πr²h

Answer 2

Answer:

Step-by-step explanation: