Question

Find the total surface area of a cone if its slant height is 21 m and diameter of its base is 24m
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Answer 1

$\bf{\underline{Question:-}}$

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

$\bf{\underline{Given:-}}$

• slant height is 21
• diameter of its base is 24m
• Radius (r) = 24/2 = 12m

$\bf{\underline{Solution:-}}$

• Total surface area of cone = πr ( l + r )

† Substituting values in formula :-

→ πr(r+l)

→ π(12)(12+21)

→ 12π(33)

→ 396π

→ 396(3.14)

→ 1243.44 m²

________________________

OR { IF WE TAKE π = 22/7 }

SO,

→ π(12)(12+21)

→ 12π(33)

→ 396 × π

→ 396 × 22/7

→ 396/7 × 22

→ 1244 .50 m²

________________________

$\bf{\underline{Hence:-}}$

• The Total Surface area of cone is 1243.44m²

Answer 2

➠ AnSwer :-

➝ Given :-

• slant height of cone ;l = 21m
• Diameter of cone = 24m
• radius ; r= 12 m

➝ To find :-

• area of cone

➝ Solution :-

→ Total surface area of a cone = πr(r+l)

→ π(12)(12+21)

→ 12π(33)

→ 396π

→ 396(3.14)

→ 1243.44

Hence, the total surface area the cone is 1243.44 m²