Switch to Perspectives Geometry. – Show the Input Bar (View menu). Set the number of decimal places to 0 (menu Options Rounding). – Introduction of new tool Midpoint or Center New! Hint: Select two points, one segment, circle or conic to get the midpoint or center. Hints: to read the Toolbar help if you know how to use a tool. Don’t forget don’t Try out the new tool before you start the construction. Construction Steps 1 Create a triangle ABC with counter clockwise orientation. 2 Create the angles and of triangle ABC. α, β γ Create a slider for angle with Interval to and Increment δ 0˚ 180˚ 3 10˚. Create a slider for angle with Interval to and Increment ε 0˚ 180˚ 4 10˚. 5 Create midpoint D of segment AC and midpoint E of segment AB. 6 Rotate the triangle around point D by angle (setting clockwise). δ Rotate the triangle around point E by angle (setting ε 7 counterclockwise). 8 Move both sliders and to show δ ε 180˚. 9 Create angle using the points ζ A’C’B’. 10 Create angle using the points C'1B'1A'1 . η 11 Enhance your construction using the Stylebar. Hint: Congruent angles should have the same color. Create dynamic text displaying the interior angles and their values 12 (e.g. and select from Objects). α α = Calculate the angle sum using 13 α β γ sum = + + Insert the angle sum as a dynamic text: and select α β γ + + = 14 sum from Objects. Match colors of corresponding angles and text. Fix the text that is 15 not supposed to be moved.
Switch to Perspectives – Geometry. Show the Input Bar (View menu). Set the number of decimal places to 0 (menu Options – Rounding). Introduction of new tool Midpoint or Center New! Hint: Select two points, one segment, circle or conic to get the midpoint or center. Hints: Don’t forget to read the Toolbar help if you don’t know how to use a tool. Try out the new tool before you start the construction. Construction Steps 1 Create a triangle ABC with counter clockwise orientation. 2 Create the angles α, β and γ of triangle ABC. 3 Create a slider for angle δ with Interval 0˚ to 180˚ and Increment 10˚. 4 Create a slider for angle ε with Interval 0˚ to 180˚ and Increment 10˚. 5 Create midpoint D of segment AC and midpoint E of segment AB. 6 Rotate the triangle around point D by angle δ (setting clockwise). 7 Rotate the triangle around point E by angle ε (setting counterclockwise). 8 Move both sliders δ and ε to show 180˚. 9 Create angle ζ using the points A’C’B’. 10 Create angle η using the points C'1B'1A'1 . 11 Enhance your construction using the Stylebar. Hint: Congruent angles should have the same color. 12 Create dynamic text displaying the interior angles and their values (e.g. α = and select α from Objects). 13 Calculate the angle sum using sum = α + β + γ 14 Insert the angle sum as a dynamic text: α + β + γ = and select sum from Objects. 15 Match colors of corresponding angles and text. Fix the text that is not supposed to be moved.
ggb-intro-en44-2014-07-17.docx