Răspuns :
la 1 aplici teorema lui pitagora si obtii:
BC²=AB²+AC² ⇒
13²=AB²+5²
169=AB²+25
AB²=169-25
AB²=144
AB=12 dm
BC²=AB²+AC² ⇒
13²=AB²+5²
169=AB²+25
AB²=169-25
AB²=144
AB=12 dm
1)AB= √13^2-5^2= 12
2)AC =20sin50
AB= 20cos50
cos C = AB/20
deci AB = 20cos C
2)AC =20sin50
AB= 20cos50
cos C = AB/20
deci AB = 20cos C