Seriously. How? There are five of them. Do i just eye ball it and risk getting it all wrong or is there an exact way of achieving it?
Use the Spin tool.
Create 1/5 of the chair base then move the 2D cursor to the center of the chair.
The 2D cursor will be the center of the Spin.
In Top view select the 1/5 chair base and then use the spin tool to create the other legs.
Use the Spin settings as shown in the screenshot below.
you could use a array, or just select one and press g+any number, to move that many blender units