Question

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

Answer 1

Answer :

• The total surface area of cone is 1244.57m².

Step-by-step explanation ::

To Find :-

• The total surface area of cone

Solution :-

Given that,

• The slant height of the cone = 21m
• Diameter of it's base = 24m

∴ Radius is,

➞ Diameter / 2

➞ 24 / 2

➞ 12m.

As we know that,

Total surface area of cone = πr ( r + L ),

Where,

• π = 22/7
• r = radius
• L = slant height

According the question,

The total surface area of cone is,

➞ Total surface area = πr ( r + L )

➞ 22/7 × 12 × ( 12 + 21 )

➞ 22/7 × 12 × 33

➞ ( 22 × 12 × 33 ) / 7

➞ ( 726 × 12 ) / 7

➞ 8712/7

➞ 1244.57

The total surface area of cone is 1244.57m².