To measure points on A triangle first you must create a triangle by clicking on draw or construct at the top of the screen. After you have selected and draw your triangle to the size of your choice you can now measure. To measure simply click on measure distance. Click on your first point you want to measure from and name it, and then move on to your next point after clicking ok to the second point the distance should appear. Repeat this step for the other points. Below is a example.