Question

the csa of a right circular cone of height 15cm and base diameter 16cm is

Answer 1

your answer is 427.24 (approx.)

Answer 2

Aɴsᴡᴇʀ:

• The curved surface area of cone = 427.04cm²

Gɪᴠᴇɴ:

• Height of cone is 15cm.
• Diameter of cone is 16cm.

Nᴇᴇᴅ Tᴏ Fɪɴᴅ

• The Curved surface area of cone = ?

Solution:

Fᴏʀᴍᴜʟᴀ ᴜsᴇᴅ ʜᴇʀᴇ:

• Diameter = Radius × 2

Pᴜᴛᴛɪɴɢ ᴛʜᴇ ᴠᴀʟᴜᴇs:

» 16 = Radius × 2

»Radius = 16/2

» Radius = 8cm

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♲︎︎ In Case 1:

Fᴏʀᴍᴜʟᴀ ᴜsᴇᴅ ʜᴇʀᴇ:

• l² = h² + r²

• l = √h² + r²

Pᴜᴛᴛɪɴɢ ᴛʜᴇ ᴠᴀʟᴜᴇs

➦ l = √(15)² + (8)²

➦ l = √225 + 64

➦ l = √289

➦ l = 17cm

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♲︎︎ In Case 2:

Aɢᴀɪɴ, Fᴏʀᴍᴜʟᴀ ᴜsᴇᴅ ʜᴇʀᴇ

• CSA of circle = πrl

Pᴜᴛᴛɪɴɢ ᴛʜᴇ ᴠᴀʟᴜᴇs:

➦ CSA of circle = 3.14 × 8 × 17

➦ CSA of circle = 3.14 × 136

➦ CSA of circle = 427.04cm²

Tʜᴇʀᴇғᴏʀᴇ

• The curved surface area of cone is 427.04cm².

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