An isosceles triangle is a triangle with two congruent sides and congruent base angles. congruent means equal. No matter which direction the triangle's apex, or peak, points, it's an isosceles triangle if two of its sides are congruent.
Uses of talc: Talc is used in a wide variety of products that we see every day. It is an important ingredient in rubber, a filler and whitener in paint, a filler and brightening agent in high-quality papers, and a primary ingredient in many types of cosmetics.
Talc, Mg 3 Si 4 O 10 (OH) 2, is always found in metamorphic settings. Talc is the softest mineral, the standard for hardness grade 1 in the Mohs scale. Talc has a greasy feel and a translucent, soapy look. Talc and pyrophyllite are very similar, but pyrophyllite (which has Al instead of Mg) may be slightly harder. Talc is very useful, and not just because it can be ground into talcum powder -- it's a common filler in paints, rubber, and plastics too.