Question

Find the total surface area of this cone.

Answer 1

Answer:

Step-by-step explanation:

Total surface area of a cone is given by the expression,

SA = πrl + B

Here, r = Radius of the circular base

l = slant height

B = Surface area of the base

Surface area of the circular base = πr²

                                                       = π(5)²

                                                       = 25π cm²

Slant height 'AC' = $\sqrt{AB^2+BC^2}$

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

                            = $\sqrt{5^2+(12)^2}$

                            =  13 cm

Substitute the values in the expression of surface area,

SA = π(5)(13) + 25π

     = 65π + 25π

     = 90π cm²

Therefore, SA = 90π cm² will be the answer.