Question

In ∆XYZ, /_X=45° , /_Y =90° , XZ=18, find XY .

Answer 1

/_ x = 45°

/_y = 90°

xz = 18

if you have know trigonometry so ,

$\cos(45) = \frac{xy}{xz} \\ \\ \: \: \: \: \: \: \: \: \: \frac{ \sqrt{2} }{2} \: = \frac{xy}{18} \\ \\ \: \: \frac{18 \sqrt{2} }{2} = xy \\ \\ \frac{18 \sqrt{2} }{ \sqrt{2} \times \sqrt{2} } = xy \\ \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \frac{18}{ \sqrt{2} } = xy \: \: \: \: \: \: \: \: or \: \: \: \: \: \: \: 9 \sqrt{2 } = xy$

i hope this point is clear .ʘ‿ʘ