Question

Sebuah segitiga ABC, dengan panjang BC = 2 cm, AB = 4 cm, Ð B = 60º. Panjang AC adalah ......... ( Aturan Cosinus )

Answer 1

To solve this problem we have to use the laws of cosine that is the extension of the Pythagoras theorem. If the triangle is ABC then we have here,  AC^2= AB^2+BC^2-[2*AB*BC*cos(B)].

Right parenthesis is used here to avoid any problem, Therefore, we have putting the numbers here, AC^2= 16+4-[2*4*2(1/2)], AC^2 = 20-8, AC^2=12, AC = sqrt(12)