Question

the side of an equilateral triangle is 2/3 cm. the perimeter of the triangle is ??​

Answer 1

r=inradius of circle, R=circumradius, A=area of triangle, S=semi-perimeter of triangle

Area of  equilateral triangle=  

4

3

​  

 

​  

side  

2

 

=>  

4

3

​  

 

​  

×(20  

3

​  

)  

2

 

=>300  

3

​  

 

Now,

S=  

2

20  

3

​  

+20  

3

​  

+20  

3

​  

 

​  

 

=>S=30  

3

​  

 

Now,

r=A/S

=>  

30  

3

​  

 

300  

3

​  

 

​  

 

=>10

According to formulae,

R=2r

=>R=20cm.