Question

1) Find CSA of a cone whose radius is 7 cm and height is 10 cm?​

Answer 1

Answer:

$\bigstar{\bold{CSA\:=\:268.4\:cm^{2} }}$

Step-by-step explanation:

$\Large{\underline{\underline{\bf{Given:}}}}$

• Radius of cone (r) = 7 cm
• Height of cone (h) = 10 cm

$\Large{\underline{\underline{\bf{To\:Find:}}}}$

• Curved Surface Area (CSA) of cone

$\Large{\underline{\underline{\bf{Solution:}}}}$

→ First we need to find the slant height (l) of the cone which is given by the equation,

$l\:=\:\sqrt{r^{2}\:+\:h^{2} }$

→ Substituting the given datas, we get the slant height

  $l\:=\:\sqrt{7^{2}\:+\:10^{2} }$

 $l\:=\:\sqrt{49\:+\:100}$

 $l\:=\:\sqrt{149} =12.2\:cm$

→ The formula for CSA of a cone is given by

   CSA = π × r × l

→ Substitute the datas, we get

    $CSA\:=\:\dfrac{22}{7} \times7 \times12.2$

    $\boxed{\bold{CSA\:=\:268.4\:cm^{2} }}$

$\Large{\underline{\underline{\bf{Notes:}}}}$

→ The CSA of a cone is given by the formula

  CSA = π × r × l

→ The TSA of a cone is given by the formula

   TSA = CSA + Base area

   TSA = (π × r × l) + πr²

   TSA = πr (r + l)