This lesson is taken from Maria Miller's book Math Mammoth Geometry 1, and posted at with permission from the author. Could an equilateral triangle be a right triangle? The three angle measures add up toĭifferent-looking triangles with this information, or are they all identical?ġ4. Draw an isosceles triangle with 75° base angles.
So that you get an isosceles triangle with 40° base angles. _ °, _ °, and _ °.Īre two angles in an isosceles triangle that haveĭraw another angle of 40° at B, and then continue its side The two angles adjacent to the base are the base angles. If it has exactly two congruent sides, then they are the legs of the triangle and the non-congruent side is the base. Then, measure off the two congruent sides, making sure they haveī. A triangle is an isosceles if it has at least two congruent sides. Those of your classmates, or draw anotherĭraw any angle. Draw an isosceles right triangle whose two sides Draw a scalene obtuse triangle where one side is 3 cm and another is 7 cm.ĭraw the 7-cm side first, then the 3-cm side forming any obtuse angle with theĬompare your triangle to those of your classmates, or draw anotherĭifferent-looking triangles with this information,ħ. Plot in the coordinate grid an acute scalene triangle.Ħ. “equilateral,” “isosceles,” or “scalene” (by their sides). Or “obtuse” (by their angles), and also as Fill in the table by classifying the triangles labeled as (a), (d), (e), and Lastly, if none of the sides of a triangleĪre congruent (all are different lengths),Ģ. “equal”, and lateral means “sided.” Think of itĬongruent, then it is called an isosceles triangle.Īs a “same-legged” triangle, the “legs” being the Length), it is called an equilateral triangle.Įqui- refers to things that are the “same” or This 5th grade geometry lesson defines equilateral, isosceles, and scalene triangles, and has a variety of exercises, including drawingĮxercises, about these topics for students. Menu Equilateral, Isosceles, and Scalene Triangles