HOW TO USE GEOGEBRA FOR ONLINE TEACHING | ANGLES | TRIANGLES | SLIDERS | RATIO | TIP FOR TEACHERS

The speaker begins by introducing a tutorial on how to draw angles with specific measurements using a tool that was previously mentioned in an introduction session. They open a new file and proceed to use the angle tool to draw an angle by marking points on the screen. The coordinates of the points are displayed, and the speaker demonstrates how to clear the graphics screen if needed. They then select a blank white paper with axes to draw on and proceed to draw an angle by marking points A, B, and C. The tool automatically calculates and displays the angle measurement, which in this case is 106°. The speaker then shows how to format the angle by hiding certain elements and adjusting the style, including color and line thickness.

The speaker continues by customizing the display of the angle by hiding specific points and adding arrows to the lines. They explain how to adjust the style of the line, including its size, decoration, and arrowheads. The process involves selecting the line, accessing its settings, and modifying the line style, such as adding an arrow at the end. The speaker also demonstrates how to hide points at the endpoints of the lines to clean up the appearance of the angle diagram. They mention the use of the move tool to resize the angle and how to fix certain points to maintain specific measurements while adjusting others.

The tutorial then moves on to drawing an angle with a given size. The speaker marks a point and then is prompted to input the angle measurement, defaulting to 45° but can be changed to any desired degree. They join the points to form the angle and note that the angle size remains fixed regardless of how the diagram is moved or resized. The speaker emphasizes the utility of this tool for creating angles with specific measurements and mentions that the tool can be used for other geometric constructions as well.

The speaker demonstrates how to construct a triangle when the length of the base and the base angles are given. They use the text tool to input the measurements and angle values, ensuring they are correctly formatted with degrees. The process involves drawing the base of the triangle with a given length and then drawing rays from the base angles to form the triangle. The speaker shows how to find the intersection point of the rays to determine the third vertex of the triangle. They rename the segments for clarity and ensure the measurements and angles are accurately represented in the diagram.

In the final part of the tutorial, the speaker introduces the use of sliders for creating variable angles. They explain that sliders are a valuable tool for teachers and can be used for various geometric constructions. The speaker sets up a slider to control the angle measurement, which can be adjusted from 0 to 360° in increments of 1°. They demonstrate how to link the slider to the angle measurement in the diagram, allowing for dynamic adjustments to the angle size. The speaker shows how the angle measurement updates automatically as the slider value changes, providing a hands-on way to explore angles and their properties.