Centering an object on top of another

Hi all… I’m working towards making a dovetail on an object and in this case I’m trying to center a smaller rectangle perpendiculaR to another larger rectangle. But I don’t know how to accomplish this… thoughts?

Hi, after you have drawn the large rectangle, the centre point is indicated and you can use this as a reference point when drawing the smaller perpendicular rectangle.

Draw a line accross the centre
Draw lines parrelel lines for smaller rectangle 1mm away from the centre line on both sides
Then delete the centre line and you will have a well centred pendicular rectangle with equal spaces at both sides

@ps23Rick
Alternatively make it easy on yourself by Sketching the two Rectangles as shown square onto the Grid set, in this case, to 0.5mm.
Make a Copy and Rotate to the Desired Angle and move it to the position required: