What is Fig. 8 called on account of its three equal sides? On account of its three equal angles? Every equilateral triangle is also equiangular. Every equiangular triangle is also equilateral. Name a triangle that has no two sides equal to each other. It is called a _scalene triangle_. What kind of a triangle is Fig. 5 on account of its right angle? What kind on account of its three unequal sides? Then it is a _right-angled scalene triangle_. What name can you give Fig. 11 on account of the angle _g e f_? On account of its three unequal sides? Then what may it be called? [Illustration: Diagram 19.] LESSON TWENTY-FOURTH. REVIEW. Name eight isosceles triangles. (DIAGRAM 19.) Why is Fig. 2 an isosceles triangle? What is an isosceles triangle? Name two right-angled isosceles triangles. Name five acute-angled isosceles triangles. Name one obtuse-angled isosceles triangle. Name two isosceles triangles that are also equilateral. Are all isosceles triangles equilateral? Name six isosceles triangles that are _not_ equilateral. What does “equi” mean? “Latus”? What are equilateral triangles called on account of their equal angles? Are all equilateral triangles equiangular? Are all equiangular triangles equilateral? What are equilateral triangles? Name four scalene triangles. Name two right-angled scalene triangles. Why is Fig. 3 a right-angled triangle? Why scalene? What is a scalene triangle? Name one obtuse-angled scalene triangle. Name one acute-angled scalene triangle. PROBLEMS. From the same point draw two straight lines of any length, making an acute angle with each other. Make them equal to each other by measuring. Join their ends. What kind of a triangle is it on account of its angles? On account of its two equal sides? Write its two names inside of it. Draw an isosceles triangle whose equal sides shall each be less than the third side. Write its two names within it. Draw an oblique straight line twice as long as any short measure or unit. At one end draw a straight line perpendicular to it, and three times as long as the same measure. Connect the ends of the two lines by a straight line. What kind of an angle is that opposite the last line drawn? Are any two of its sides equal? Write its two names under it. Draw a horizontal straight line of any length. At one end draw a vertical line of equal length. Complete the triangle, and write two names inside. Draw a right-angled triangle whose base is of any length, and its perpendicular twice as long. Draw a right-angled triangle whose base is three times as long as any short measure, and its perpendicular five times as long as the same measure or unit. [Illustration: Diagram 20.]