Răspuns :
se formeaza un triunghi dreptunghic AOB, aplici Pitagora
AB²=AO²+OB²
AB²=4²+9/2²
AB²=16+81/4
AB²=64+81/4
AB²=145/4
AB=145√4/4
AB²=AO²+OB²
AB²=4²+9/2²
AB²=16+81/4
AB²=64+81/4
AB²=145/4
AB=145√4/4