The total surface area of a right circular coneof slant height 13 cm i

1.	The total surface area of a right circular coneof slant height 13 cm is 90 cm", find itsradius and volume.
Answer» Answer: Radius = 5 cm Volume = ≈ 314 cm^3 OR 2200/7 Step-by-step explanation: It should be 90 $\pi$ cm^2 Total SURFACE AREA of right circular cone = $\pi$ R(l+r) 90 $\pi$ = $\pi$ r(13+r) 90 $\pi$ / $\pi$ = r(13+r) 90 = 13r+r^2 r^2 + 13r - 90 = 0 r^2 + 18r - 5r + 90 (By splitting the middle term) r(r + 18) - 5(r+18) (By taking common) (r-5)(r+18) r = 5 r = -18 ( radius cannot be negative) So, r = 5CM $l^{2}$ = $\sqrt{h^2+r^2}$ $13^{2}$ = $\sqrt{h^2+5^2}$ 169 = $\sqrt{h^2+25}$ h = $\sqrt{169-25}$ h = $\sqrt{144}$ h = 12 cm Volume of cone = 1/3 $\pi$ $r^{2}$ h = 1/3 * 3.14 * 5 * 5 * 12 ≈ 314 cm^3 OR 2200/7 Hope it help. PLEASE mark it as the brainliest.