Answer
Verified
393.6k+ views
Hint: To find the curved surface of the cone, we are given the perimeter of the base of a cone which is the same as the circumference of a circle, that is, $C=2\pi r$ . From this, we will get the value of r. Then, we have to substitute this value in the formula of curved surface area which is $\pi rl$ .
Complete step by step solution:
We have to find the curved surface of the cone. We are given that the perimeter of the base of the cone is 44cm. We know that the base of a cone is a circle.
We know that perimeter or circumference of a circle or cone is given by
$C=2\pi r$
where r is the radius of the cone.
$\Rightarrow 44=2\pi r$
Let us find the radius from the above equation.
$\Rightarrow r=\dfrac{44}{2\pi }$
We know that $\pi =\dfrac{22}{7}$ . Therefore, the above equation becomes
$\Rightarrow r=\dfrac{44}{2\times \dfrac{22}{7}}$
Let us cancel the common factor 22 from the RHS.
$\Rightarrow r=\dfrac{2}{2\times \dfrac{1}{7}}=\dfrac{2\times 7}{2}$
Let us cancel the common factor 2.
$\Rightarrow r=7\text{ cm}$
We know that curved surface area of a cone is given by
$\text{CSA of cone}=\pi rl$
where l is the slant height. We are given that $l=25\text{ cm}$ .
$\Rightarrow \text{CSA of cone}=\dfrac{22}{7}\times 7\times 25$
Let us cancel the common terms.
$\Rightarrow \text{CSA of cone}=22\times 25=550\text{ c}{{\text{m}}^{2}}$
Hence, the curved surface area of the given cone is $550\text{ c}{{\text{m}}^{2}}$ .
Note: Students must know the formulas of solids. Students must also know that the base of a cone is a circle. They must know the formula of the curved surface area (CSA) and total surface area (TSA) of a cone. They may get confused with the CSA and TSA of a cone. TSA of a cone is given as $\pi r\left( r+l \right)$ , where $l=\sqrt{{{r}^{2}}+{{h}^{2}}}$ , where h is the height of the cone.
Complete step by step solution:
We have to find the curved surface of the cone. We are given that the perimeter of the base of the cone is 44cm. We know that the base of a cone is a circle.
We know that perimeter or circumference of a circle or cone is given by
$C=2\pi r$
where r is the radius of the cone.
$\Rightarrow 44=2\pi r$
Let us find the radius from the above equation.
$\Rightarrow r=\dfrac{44}{2\pi }$
We know that $\pi =\dfrac{22}{7}$ . Therefore, the above equation becomes
$\Rightarrow r=\dfrac{44}{2\times \dfrac{22}{7}}$
Let us cancel the common factor 22 from the RHS.
$\Rightarrow r=\dfrac{2}{2\times \dfrac{1}{7}}=\dfrac{2\times 7}{2}$
Let us cancel the common factor 2.
$\Rightarrow r=7\text{ cm}$
We know that curved surface area of a cone is given by
$\text{CSA of cone}=\pi rl$
where l is the slant height. We are given that $l=25\text{ cm}$ .
$\Rightarrow \text{CSA of cone}=\dfrac{22}{7}\times 7\times 25$
Let us cancel the common terms.
$\Rightarrow \text{CSA of cone}=22\times 25=550\text{ c}{{\text{m}}^{2}}$
Hence, the curved surface area of the given cone is $550\text{ c}{{\text{m}}^{2}}$ .
Note: Students must know the formulas of solids. Students must also know that the base of a cone is a circle. They must know the formula of the curved surface area (CSA) and total surface area (TSA) of a cone. They may get confused with the CSA and TSA of a cone. TSA of a cone is given as $\pi r\left( r+l \right)$ , where $l=\sqrt{{{r}^{2}}+{{h}^{2}}}$ , where h is the height of the cone.
Recently Updated Pages
Who among the following was the religious guru of class 7 social science CBSE
what is the correct chronological order of the following class 10 social science CBSE
Which of the following was not the actual cause for class 10 social science CBSE
Which of the following statements is not correct A class 10 social science CBSE
Which of the following leaders was not present in the class 10 social science CBSE
Garampani Sanctuary is located at A Diphu Assam B Gangtok class 10 social science CBSE
Trending doubts
Derive an expression for drift velocity of free electrons class 12 physics CBSE
Which are the Top 10 Largest Countries of the World?
Write down 5 differences between Ntype and Ptype s class 11 physics CBSE
The energy of a charged conductor is given by the expression class 12 physics CBSE
Fill the blanks with the suitable prepositions 1 The class 9 english CBSE
Derive an expression for electric field intensity due class 12 physics CBSE
How do you graph the function fx 4x class 9 maths CBSE
The Equation xxx + 2 is Satisfied when x is Equal to Class 10 Maths
Derive an expression for electric potential at point class 12 physics CBSE