Question

dado triângulo abc,tal que:lado AB=5 cm, lado ac=8 cm, ángulo B=60⁰, calcule a medida em centímetros do lado bc.​

Answer 1

cos 60= BD/5

BD= 5 * cos 60° =5*(1/2)=5/2

sen 60 =h/5

h=5 * sen60° =5√3/2

8²=DC²+h²

64=DC²+(5√3/2)²

64=DC²+25*3/4

DC²=64-75/4

DC²=181/4

DC=√181/2

BC=BD+DC = 5/2 +√181/2=(5+√181)/2