Question

the curved surface area of cone is 4070cm2 diameter 70 cm what is it's slant height

Answer 1

diameter =70cm r=D/2= 35cm

curved surface area of cone = πrl

4070 = 22/7×35×I
4070 = 22×5×l
4070=110×l
4070/110=l
37cm = l

slant height is 37 cm

Answer 2

$\large\underline\pink{Given:-}$

• Curved surface area = 4970 m²
• Diameter = 70 cm

$\large\underline\pink{To find:-}$

• Fine the slant height circular cone ....?

$\large\underline\pink{Solutions:-}$

• Let the slant height of cone be l.
• Diameter = 70
• Radius = d/2 = 70/2 = 35

Curved surface area of cone = πrl

$\: \: \: \: \: \leadsto \: \: \frac{22}{\cancel{7}} \: \times \: \cancel{35} \: \times \: {l} \: \: = \: \: {4070}$

$\: \: \: \: \: \leadsto \: \: {22} \: \times \: {5} \: \times \: {l} \: \: = \: \: {4070}$

$\: \: \: \: \: \leadsto \: \: {110} \: \times \: {l} \: \: = \: \: {4070}$

$\: \: \: \: \: \leadsto \: \: {l} \: \: = \: \: \cancel{\frac{4070}{110}}$

$\: \: \: \: \: \leadsto \: \: {l} \: \: = \: \: {37} \: cm.$

Hence, the slant height of the cone is 37cm.

$\large\underline\pink{More \: \: Information:-}$

Right circular cone:-

• h = height of cone
• r = Radius of cone
• s = slant height

1. Volume = 1/3πr²h
2. Lateral surface area = πr √r²+h²
3. Total surface area = πr² + πr √r²+h²