A=√p(p-a)(p-b)(p-c)
p=(a+b+c)/2= (8+7+6)/2= 21/2
A=√21/2 ( 21/2 -8)* (21/2 -7)* ( 21/2 -6) aducem la acelasi numitor in paranteze
A=√21/2 (21-16)/2 * (21-14)/2 * (21-12)/2
A=√21/2 * 5/2 * 7/2 * 9/2
A=√ (3*7*5*7*3*3)/2 * 2*2*2
A=(3*7)/2*2 √3*5
A=21/4 √15
A=5,25 *3,87
A=20,33
