Find the area of a triangle whose sides are 5 cm, 7 cm and 11 cm.

Correct option is B

Given:  

Side of the tringle 

a = 5 , b = 7 , c = 11 

Formula Used:

$$\sqrt{s{(s-a)}{(s-b)}{(s-c)}}$$    

Where S = $$\frac{a+b+c}{2}$$

Solution:

S = $$\frac{5+7+11}{2} = 11.5$$   

​$$= \sqrt{11.5{(11.5-5)}{(11.5-7)}{(11.5-11)}} \\\ \\= \sqrt{11.5{(6.5)}{(4.5)}{(0.5)}} \\\ \\= \sqrt{11.5{(6.5)}{(4.5)}{(0.5)}} \\\ \\= \sqrt{11.5{(6.5)}{(4.5)}{(0.5)}} \\\ \\= 12.97$$​​

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