Question

If diameter of a cone is 12 cm. and its height 8 cm. then find the total surface area of
cone.​

Answer 1

Answer:

see below

please

Step-by-step explanation:

r= 12/2= 6 cm. , h = 8 cm. , l=√(r^2+h^2)= √(6^2+8^2) = 10 cm.

Total surface area of a cone = π.r.(l+r) units ^2.

= (22/7).6.(10+6) cm^2/

= 2112/7 cm^2.

= 301.714 cm^2. Answer.

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Answer 2

Given: Diameter of a cone= 12 cm

           Height of the cone= 8 cm

To Find- Total surface area of the cone.

Solution:

For finding the total surface area, we need the radius and slant height of the cone.

Assuming the radius of the cone to be 'r' cm.

Radius= $\frac{Diameter}{2} cm$

          = $\frac{12}{2}cm$

          = 6cm

Assuming the slant height of the cone to be l.

Slant height= $\sqrt{r^{2}+h^{2} }$ cm

⇒ l= $\sqrt{6^{2}+8^{2} }$

    = $\sqrt{36+64}$

    = $\sqrt{100}$

    = 10 cm

∴ Total surface area= πr ( l + r ) $unit^{2}$

                                = 6π (10+6) $cm^{2}$

                                = (6π $\times$ 16) $cm^{2}$

                                = 96π $cm^{2}$

Answer: The total surface area of the cone is 96π $cm^{2}$.