# A semi circular sheet with area 154 sq unit to used to from a cone without cotting the sheet. find the volume of cone thus formed.

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slant length=s

Then the curve area of cone =πRs

Area of semicircle πr²/2=πRs

⇒ πs²=2πRs

⇒ 2R=s

We have h= √(s²-R²)=√3*R

From question πRs= 2πR²=154

R²=24.509 ⇒R=4.950

Then h=√3*R= 8.574

Volume of cone=πR²h/3=220.082