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# Find the total surface area of a cone, if its slant height is 21 m and diameter of its base is 24 m.

Given :
Radius (r) of the base of cone = $$\frac{24}{2} cm = 12 cm$$
Slant height (l) of cone = 21 cm

We know that, TSA of cone
= $${\pi}r(r + l)$$
= [$$\frac{22}{7} × 12 × (12 + 21)$$ $${m}^2$$]
= [$$22 × 1.71 × 33$$ $${m}^2$$
= 1244.57 $${m}^2$$

Therefore, the total surface area of the cone is 1244.57 $${m}^2$$.