A lot of friends in PowerPoint to draw a circle and demo, you will find it is not easy to determine the center of the circle, some people just observe at the "center of the Circle" to draw a dot instead, so that in the playback may occur when the center of gravity deviation. In fact, we can use the "Concentric circle" tool button to solve this problem.
Select the AutoShape → basic shape → concentric circle command in the Drawing toolbar below the slide. Then according to the need, in the slide to draw a suitable size concentric circle, with the mouse to select the round yellow operation Point while holding down the left button, inward drag into a small dot, and then release the mouse, So we can skillfully get the exact center of the circle.
Figure 1 PowerPoint drawing concentric Circles