3. Use Pythagoras' Theorem to find the length of side [i]f[/i].
[math]f^2+\left(\frac{1}{2}\right)^2=1^2[/math][br][math]f^2+\frac{1}{4}=1[/math][br][math]f^2=\frac{3}{4}[/math][br][math]f=\sqrt{\left(\frac{3}{4}\right)}[/math][br][math]f=\frac{\sqrt{3}}{2}[/math]