Draft it Help

 

Select the 12mm diameter circle. The Polar Array button polar array button now becomes available. Select this and the prompt reads:

Give Centre Point of Array:

Before indicating the centre point you will notice that the Ribbon has changed and now displays the specific options for this command.Change the 'No.' of value  from the default value of '4' to '8' .

Now select the 'Mid' point of the vertical line or  the 'Cen' point snap at the centre of the circles (P1). The prompt changes to:

polar array options

Give Reference Point:

Select the 'Cen' point snap at the centre of the 12mm diameter circle (P2). The prompt changes to:

Give point to Array to:

Select the Polar input option polar array input mode and enter 45 into the angle input field.

polar mode input fields

This has locked the angle to 45° and as you move the cursor back into the drawing area you will see the arrayed circles positioned correctly. Click anywhere to accept the position and complete the array.

 

polar array dimensions