Two circles, circle radius of small circle radius of 3 times times, small circle in the circle of circular rolling a week back to the original position, small circle itself how many laps? Let's take a look at how to demonstrate this math problem in PowerPoint.
Draw a small circle with the ellipse tool in the drawing tool, the radius of the circle is three times times the small circle, draw a straight line as the radius of the small circle, and combine the straight line with the small circle. Draw a rectangle with the Rectangle tool and add the text "demo" to it, which is left as the trigger for the animation. Position the three graphic as shown in Figure 1.
Figure 1 Creating an Object
Set animation effects
1. Set small circle around the circle effect
Select the small circle, and in the Custom animation pane, click Add Effect/action path/Other action path ... (Figure 2), in the dialog box that appears, select the "Circle expansion" animation effect, you can see the small circle of the motion path is a circle, but this circle does not meet our requirements, select the Circle, Adjust the position and size of the circle to the center of the circle, the radius is just the radius of the circle plus the radius of the small circle. This adjustment process requires a bit of care and patience, while adjusting the shift, CTRL, and ALT keys for flexible use, as shown in Figure 3.
Figure 2 Adding a motion path
Fig. 3 Effect chart after adjustment
In the Custom Animation pane, double-click the circle extension Custom animation that you just added, the Circle Expansion Settings dialog box appears, click the Effects tab, and remove the balance start and balance end two options. Click the Timing tab, set the speed to 10 seconds (enter 10 directly inside), click the bottom (Trigger) button, select the rectangle drawn in the first step in the "Start effect when clicking the following objects", and press (OK) to close the dialog box (Figure 4).
Figure 4 Graphic expansion
2. Set Small circle spin effect
Continue to select the small circle, and click Add Effect/accent/spin in the Custom animation pane. Double-click the spin effect you just added, and the Spin Settings dialog box appears (Figure 5), clicking the Effects tab, setting Quantity to 1440° (this must be entered manually). Click the Timing tab to set start to before (so that the two animation effects will be synchronized), set to 10 seconds (the same time as the previous animation effect), and, similarly, set the trigger to a rectangle. Press (OK) to close the dialog box.
Figure 5 Gyro Spin dialog box
By F5 the slide show, you can see the final effect. Because of the use of triggers, in the actual use, you can repeatedly play the animation, to facilitate the students to observe carefully, so that the correct answer.