Question

Diameter of the base of a cone is 10.5 cm and its slant height is 10 cm. Find its curved surface area.

Answer 1

Hello!

• Radius, r = $\bf{5.25\: cm}$
• Slant height, l = $\bf{10\:cm}$

Then,

$\underline{\bf{Curved \:surface\:area\:of\:Cone}}$ :

$\sf πrl \\ \\ \implies \dfrac{22}{7} \times 5.25 \times 10 \\ \\ \implies \dfrac{1125}{7} \implies \boxed{\red{\bf{165\:cm^{2}}}}$

Cheers!

Answer 2

Answer:

$165\ cm^{2}$

Step-by-step explanation:

In the question, diameter (d) of the base of a cone = 10.5 cm

slant height (l) of cone = 10 cm

Radius (r) of the base of cone = $\frac{d}{2}$

                                                  $=\frac{10.5}{2}$

                                                  = 5.25 cm {since we know that, d = 2r}

As we know that,

Curved surface area of cone = πrl

                                                = $(\frac{22}{7}\times5.25\times10) cm^2$

                                                =  $(\frac{22}{7}\times\frac{525}{100}\times10) cm^2$

                                                =  $(22\times\frac{75}{100}\times10) cm^2$

                                                = $\frac{16500}{100}$

                                                = $165\ cm^{2}$

Hence the curved surface area of cone is $165\ cm^{2}$.