This literally is half an equilateral triangle, a 30/60/90 triangle, the biggest cliche in trigonometry. You should memorize that the sides are in ratio
[tex]1:\sqrt{3}:2[/tex]; then
[tex]x = 16/2 = 8[/tex]
[tex]y = (16/2) \sqrt{3} = 8 \sqrt 3[/tex]
If we didn't know that, we could see that the altitude bisects the equilateral triangle's side, so 16=2x, i.e. x=8. Then [tex]x^2+y^2=16^2[/tex] so
[tex]y = \sqrt{16^2 - x^2} = \sqrt{16^2-8^2} = \sqrt{8^2(4) - 8^2} = 8 \sqrt{3}[/tex]
Answer: x=8, y=8√3
