Please answer it now in two minutes

Can someone me and do the problem plz so i can understand it more better

[10 points, algebra 2]according to my answer key the restrictions are -1 and 4. but why not positive 1?

Right triangle xyz has a right angle at vertex y and a hypotenuse that measures 24 cm. angle zxy measures 70º. what is the length of line segment xy? round to the nearest tenth. 8.2 cm 8.7 cm 22.6 m 25.5 cm