JAMB - Mathematics (1997 - No. 31)
In a triangle XYZ, if < ZYZ is 60, XY = 3cm and YZ = 4cm, calculate the length of the sides XZ.
√23cm
√13cm
2√5cm
2√3cm
Vysvětlení
(XZ)2 = 32 + 42 - 2 x 3 x 4 cos60o
= 25 - 24\(\frac{1}{2}\)
XZ = √13cm
= 25 - 24\(\frac{1}{2}\)
XZ = √13cm