Step 3. From B swing an arc equal to BP and from1. The altitude of a triangle is a line drawn from thethis intersection with the circle, draw thevertex, perpendicular to the base.diameter, thus dividing circle O into 8 equal2. The median of a triangle is a line drawn from thevertex to the midpoint of the base.TRIANGLESA triangle is a plane shape having 3 sides. Its nameis derived from its three (tri) angles.Other facts help define a triangle.1. The sum of the angles in any triangle equals180°.2. A triangle is the only plane shape which maybedefined in terms of its sides only; in all othersone or more angles must be stated.Types of TrianglesThere are four kinds of triangles. They are classifiedaccording to the size of their sides and angles as follows:1. Equilateral-all sides are equal-all angles areequal-all angles are 60°2. Isosceles—two sides equal-two angles equal3. Scalene—all sides unequal-all angles unequal4. Right—one right angleAltitudes and MediansThe altitude and median of a triangle are not thesame; the difference is pointed out in the followingdefinitions:Construction of TrianglesThere are many ways to construct a triangle, de-pending upon what measurements are known to you.The following examples will assist you. Select the ap-propriate method according to the information givenabout the triangle.1. A triangle may be constructed if the lengths ofthree sides are known.Problem:Construct a triangle.Given:Three sides of a triangle: 2“, 1“, 1 1/2”.AII-9