10000000000000000000000000000000000000000000 Points1) Find the curved

1.	10000000000000000000000000000000000000000000 Points1) Find the curved and surface area and volume of the cone whose radius of base 21 cm and height 28cm?
Answer» $\huge{\bf{\underline{\red{Solution :}}}}$ GIVEN, HEIGHT of the cone = 28 cm Radius of BASE = 21 cm To Find, CURVED SURFACE area = ? Total surface area = ? Volume of the cone = ? Find, ⇒Firstly we find the slant height of the cone . ∴Slant height of the cone( l ) = $\bold{\sqrt{r^{2} + h^{2} }}$ $\implies \bold{l = \sqrt{ 21^{2} + 28^{2} }}$ $\implies \bold{ l = \sqrt{ 441 + 784}}$ $\implies \bold{l = \sqrt{ 1225}}$ $\implies \boxed{\bold{ l = 35 \ cm }}$ Now Curved Surface Area :- $\implies \boxed{\bold{ Curved \ Surface \ Area = \pi rl}}$ $\implies \bold{\frac{22}{7} \times 21 \times 35}$ $\implies \boxed{\bold{2310 \ cm^{2}}}$ Now Total Surface Area :- $\implies \boxed{\bold{Total \ surface \ Area = \pi r(l + r})}$ $\implies \bold{\frac{22}{7} \times 21(35 + 21)}$ $\implies \bold{22 \times 3 \times 56 }$ $\implies \boxed{\bold{3696 \ cm^{2}}}$ Now Find the Volume of the Cone :- $\implies \boxed{\bold{ Volume \ of \ the \ cone = \frac{1}{3} \times \pi r^{2} h}}$ $\implies \bold{\frac{1}{3} \times \frac{22}{7} \times 21 \times 21 \times 28}$ $\implies \bold{22 \times 3 \times 7 \times 28}$ $\implies \boxed{\bold{12936 \ cm^{3}}}$ $\rule{200}2$