Ключевые слова: angle, background, black, blackboard, chalk, chalkboard, closeup, college, color, copy, degrees, design, drafting, drawing, education, engineering, equipment, female, geometry, hand, item, knowledge, learn, learning, length, line, markings, math, mathematical, mathematics, measure, measurement, measuring, number, person, protractor, ruler, school, science, shape, space, stationery, study, supplies, teach, text, tool, university, woman, work,