Total surface area of a cone is given by,
Here, l = Slant height of the cone, r = radius of the circular base and B = Area of the base
Total surface area of the cone will be 324π in².
From the picture attached,
Substitute these values in the formula of the surface area,
Area of the circular base = πr²
= π(12)²
= 144π in²
Total surface area of the cone = π(12)(15) + 144π
= 180π + 144π
= 324π in²
Therefore, total surface area of the cone is 324π in².
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